根据下列句子及所给单词的首字母，在答题卷上按题号写出各单词的完全形式（每空限填一词）。
⑴My grandfather likes to water the f____  in the garden on weekends.
⑵The boy is too young. So don't leave him a____  at home.
⑶If I don't help my mom do some h____  on weekends, my mother will be very angry with me.
⑷Last night I didn't go to bed u____  the TV program was over.
⑸Last Sunday I w____  a letter to my father.
⑹I need to look smart for my job i____ .
⑺He f____  his test last week. He should study hard.
⑻He m____  his teacher in the street yesterday.
⑼When the little girl saw the big tiger, she felt very s____ .
⑽Last week, I p____  500 yuan for my new bike.

小美在植树节和同学们去植树，同学们一共需要植20棵树，小美植了3棵树，小明植了5棵树，老师看他们树植的很快，又分给了他们5棵树，问其他同学一共需要植多少树?

两列火车，甲车每秒钟行20公尺，乙车每秒行12公尺，当车尾相齐，甲车尾越过乙车头时耗时30秒，车头相齐，甲车尾越过乙车头时耗时40秒，则甲、乙车身长各为几公尺？