答得好加悬赏1.There is ____(a/an)"s"in the word "desk"请说明如何区分元音单词

答得好加悬赏
1.There is ____(a/an)"s"in the word "desk"请说明如何区分元音单词
2.we spend an hour finishing _____(the/不填)说明原因
3.____(that ,this)is all i wanted to say 说明理由
4.I' m afraid get an injection is ____(much too;a lot )原因
5.He returned ____(at /on)a rainy night 正确答案是at.但是不是说具体的一天用On
6.解释下括号里为什么用这个时态She always (studied)something whenever she(played)
7.-has Tom finished his homework today?-I have no idea .He (was doing )it this morning 括号里为什么不用现在完成时?
8.They were (frightened)at the sudden noise 为什么不用fighting?
9.Lucy ,you clean the blackboard today ,(will you)请解释为什么用括号里的.
不好意思。第2题横线后面加个work.第4题横线后面加一个painful.我漏打了。能再回答下吗？