有几道题不解，跪求答案！

1、sleeping一词中的字母拼出三个有四个字母组成的单词
2、谜语 What is it that,when once lost, you can never find again?
3、谜语 What is it that we never borrow but often return?
4、看音标写单词 [ə'təek]
5、根据句意和所给的字母，补全单词
They have made a d- - -s- - - at the meeting.
Necessity is mother of- -ven- - - -.
The milkman comes r- - -l- - - - every day.
I e- - - - - that I can see you soon.
“Paper” is one of old i - - -t- - -s in China.
Li Ming is an op- - -t-r 999 in Beijing.
The doctor gave her some m- - - - - - - and soon she woke up.
Guo Jingjing is an e- - -l- -nt swimmer.
Lei Feng was a great s- - - - - - in his army.
That young man has just performed an o- - - - - - - - on his sick day.
Can you i- - - - - - - - yourself to your classmates,Simon?
My favorite sport is s- - - - - in winter.
Don't be a- - - - -.I'll go with you if it is dark.

求一小学数学题答案．实在不解！ 跪求题解！！会而不解的是“鳖”！ 新概念英语3的不解答案 困惑，不解，求高人帮忙 ~~不解~~ 不解^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 不解~~~~~~~~~ 不解................ 不解............................... 不解....