A. After a while, the sign began to look like this… .
B. After a while, the sign began to look like this +.
C. After a while, the sign began to look like this &.
6. The main idea of the whole story is that ______.
A. the signs for adding and subtracting have changed.
B. People could not write in the 1500s
C. the old signs were good for Egyptians but not for us
Key: 1.D 2.substract 3.signs 4.C 5.A 6.A (四)
Mexico's neighbours are the United States to the north and
Guatemala and Belize to the south. Mexico is about one quarter of the size of the United States. Mexico has more than ninety million people. The language of Mexico is Spanish. This makes Mexico the world's largest Spanish-speaking country.
