浸泡法是稀释（），把根据需要消毒的物品浸泡其中，持续一定的时间。
A.药物
B.洗洁净
C.肥皂
D.消毒剂
参考答案：D
用所给单词的适当形式完成句子。
1. _____ (teenage) want to go to the Watertown.
2. It is not easy for the disabled to become _____ (hero).
3. I take the girl to school _____ (safe).
4. You can take the escalator to the _____ (two) floor and turn right.
5. —What are some of the _____ (advantage) of the web?
—You may waste your time playing games. Sometimes you may be cheated online.
如图，M1=5千克M2=10千克，M2的底面积为10c㎡，忽略绳重及摩擦，求M2对地面的压强．
