D. Those moments can do nothing about their daily frustrations.
20. From the last sentence of the passage we can infer that__________.
A. Moms have only the smiley feeling about childcare.
B. Moms feel frustrated at taking care of their children.
C. Moms enjoy doing housework as a part of their childcare.
D. Moms regard childcare as a meaningful part of their lives.
Passage Two
Do you go to bed without brushing your teeth? You may think that not brushing is not a big deal. But caring for yourmouth can prevent serious (and even embarrassing) problems.
Cavities happen to just about everyone. A cavity is a diseased spot in the tooth. It all starts with a sticky film made upof bacteria. That film coats your teeth and gums. The bacteria eat sugars from things you eat and drink. That produces acids.
Then, the acids eat away at your teeth's hard outer coating, called enamel.
If you don't brush regularly to remove the film, or if you keep missing a spot, those acids keep eating away the teeth'senamel. That is how you get a cavity. "The larger it gets, the closer it gets to the nerve, increasing the chance of severe pain,"says Lynn Ramer, president of the American Dentists' Association.
A cavity will never just go away by itself. It will only get worse. "Left untreated, 100 percent of the time a cavity willspread," says Dr. William Berlocher, a dentist who is also president of the American Academy of Pediatric Dentistry.
If a cavity is caught early enough, your dentist will be able to fix your tooth. The area of the tooth where the cavity waswill be replaced with a special material called a filling. Some fillings are made of a metal blend containing silver. Otherfillings are a tooth-colored mix of glass and a strong material called resin.
If you ignore a cavity, it will spread. It can go into the tooth's root. At that point, the dentist will have to do a root canal.In that procedure, the dentist removes the tooth's nerve.
21. According to the second paragraph, what is a cavity?
A. a diseased spot in the tooth
B. a film of acids coating the teeth
C. a sticky film made up of bacteria
D. a hard outer coating covering the teeth
22. What would happen if you do not brush regularly?
A. The film coating your teeth would be removed.
B. There would be less diseased spots in your teeth.
C. The film coating your teeth would be less sticky.
D. The acids would keep eating away your teeth?s hard outer coating.
23. If a cavity reaches the tooth?s root, how would a dentist treat it?
A. Replace the cavity with a filling
B. Replace the tooth?s enamel
C. Remove the tooth?s nerve
D. Pull out the tooth
24. According to the fifth paragraph, what are some fillings made of?
A. a mix of silver and resin
B. a metal blend containing glass
C. a metal blend containing copper
D. a mix of glass and resin
25. The main purpose of the passage is to __________.
A. explain the formation and treatment of cavity
B. emphasize the importance of brushing teeth
C. discuss the proper ways of brushing teeth
D. describe how a dentist treats a cavity
Passage Three
Small talk is like having loose change in your pocket. Like quarters for a pay phone, loose change comes in handywhen you least expect it. But when it comes to small talk, you must know when to spend it or save it.
All small talk is not the same. With some people, you walk away having killed a few moments. With others, you feel aconnection and want to get to know them better. The difference is the effort one or both of you made at making a connection.
It helps to call the person by name, mention things you have in common (mutual acquaintances, places you've been,experiences you've shared, career or personal goals), show interest in that person's views or hobbies, and match the otherperson's speaking style, voice, emotion and body language as you talk.
People feel being related to others who like them, appreciate them, enjoy the same things they do and are helpful tothem. Time and attention make connections that last.
When you're considering small talk, be sensitive to the other person's mood and circumstances. When your airplaneseatmate is obviously preoccupied, leave him or her alone. Neither would you approach someone when the person isdashing down a hallway to a meeting. On other occasions, small talk is inappropriate because of the person involved. If theCEO has unexpectedly called you in for "a little chat," this is not the time to take the lead. Let him or her dictate the topicand pace. The same is true with customers. Develop a sixth sense about those who appreciate small talk and those who don't.
26. What is the meaning of the underlined phrase comes in handy in the first paragraph?
A. becomes very useful
B. becomes very special
C. becomes very important
D. becomes very inconvenient
27. According to the second paragraph, how can you make a connection with others
A. mention your unique experiences
B. describe others? dressing styles
C. talk about others? hobbies
D. discuss others? names
28. If you want to make others? feel related to you, you may need to__________.
A. spend time chatting with them
B. show how excellent you are
C. give presents to them
D. be helpful to them
29. According to the fourth paragraph, on what occasion should you avoid making small talk with others?
A. when others are strolling on the street
B. when your airplane seatmate asks you for a favor
C. when your airplane seatmate is absorbed in thought
D. when others are walking down the hallway after a meeting
30. According to the last paragraph, what should you do when your CEO has unexpectedly called you in for “a little chat”?
A. let the CEO dictate the topic and pace
B. talk about the difficulties in your work
C. take the lead to make small talk
D. decide on the topic of talk
Passage Four
A biological clock is what tells plants, animals, and other organisms how to organize their time. This ?clock? helpsplants and animals change their routine when they move to places with different climates and environments. Most biologicalclocks are based on the movement of the sun and follow a twenty-four hour cycle called a circadian rhythm. Some animalssleep only at night, making them diurnal. Animals that sleep during daytime are nocturnal. Flowers are diurnal because theyclose their petals at night but they open again in the morning. Bats sleep in the daytime so they are nocturnal.
Some biological clocks also follow an annual cycle, especially in animals that have annual migrations. Animals thathave annual cycles do different things at different times of year. Their actions are determined by the seasons.
Different animals can live in the same area when their biological clocks make them look for food at different times ofday. This process also keeps them out of each other's way. Biological clocks help plants and animals prepare for changes inthe seasons. Animals need to know what time of year to reproduce so their offspring will be born when the conditions forsurvival are good.
Human beings' sleep cycle is a circadian rhythm, a system based on the twenty-four hour day. In the circadian rhythmmost humans sleep at night. When people travel to different time zones their biological clocks have to adjust. In humans, thebiological clock is in a group of cells called the suprachiasmatic nucleus (SCN.) The SCN is located near the bottom middlepart of the brain.
Scientists are continuing to research the biological clock and circadian rhythms. Scientists discovered the first circadiangene in a mammal (a mouse) in 1997. It is only a matter of time before your own biological clock will tell YOU the time!
31. Which of the following type of animal or plant is nocturnal?
