阅读理解。

     Tom is studying in a village school. There are two hills not far from his home. There is a valley (山谷)

between the two hills. The school is in the middle of the valley. He walks to school every day. There is a

small river in front of the school. There is a stone bridge over the river. There is a big playground behind

the teaching building. There are some big trees near the classroom building and the children often read and

play under the trees after school. There are many fields (农田) near the school. When autumn comes, all

the teachers and students will help farmers with their harvest.

1. Tom's school is _______.

A. in a big city

B. in a small town

C. on a hill

D. in a valley

2. Tom goes to school _______ every day.

A. on foot

B. by bike

C. by bus

D. by car

3. The word "bridge" means _______.

A. 小路

B. 小山

C. 桥

D. 船

4. There are some _______ in Tom's school.

A. trees

B. students

C. fields

D. A and B

5. Students in Tom's school ______ read and play in their school.

A. like to

B. don't like to

C. sometimes

D. seldom

WLAN规划和设计中，覆盖区域的PingAC时延要求不高于（）ms。

A、20；

B、30；

C、40；

D、50。