(   ) 4.      is helpful to our environment.

   A. Cutting down trees   B. Killing animals

   C. Stopping riding in cars   D. Recycle paper

(   ) 3. ―What        the number of the students in your school?

      一About two thousand. A number of them from the countryside.

   A. is;are   B. is;is   C. are;is   D. are;are

(   ) 2. When you leave,please turn off the lights      energy.

   A. save   B. saving   C. saved   D. to save

(   ) 1. The man stopped       when he saw a sign of danger.

   A. drive   B. to drive   C. driving   D. driven

5. You'd better take your own bags when       (购物) .

4. Use a        (餐巾) to wipe your mouth after eating.

3. Don't forget to        (关掉) the lights when you leave the room.

2. The boys are        (骑) their bikes around the streets.

1.        (回收利用) paper is really easy for us.

5. recycle books