早上遇见刘老师，应说：
A. Thank you, Mr. Liu.
B. How?
C. Good morning, Mr. Liu.
补全对话。（5%）
A:last Sunday?
B: Yes, I did. My classmates and I went to plant trees.
A: How did you plant trees?
B: First, we in the ground. Then, we
and put them into the holes.
After that, we . We watered the young trees.
A:?
B: Yes, they are. They can stop the wind and they can make the air fresh and clean.
A: We should plant more trees.
The White House is in .
A. France B. China C. Washington
Our teacher always tells uswaste water.
A. to not B. not to C. not
We should turn the lights when we leave the room
A. on B. off C. in
We shouldn’t cut downtrees and wastewater.
A. too many ; too many B. too many; too much C. too much; too much