1、Kelly and I are arriving at home at 8 o' clock in the even

1、Kelly and I are arriving home at 8 o' clock in the evening?
(为什么此句中at要省略） home是副词,前面不能有介词
2、Ask your classmates ( ) who you're describing.答案：A
A.to guess B.guess C.guessing D.guesses 固定用法 ask sb.to do sth.
3、You ( ) go and ask Ruth ,she ( )know the way to the airport.答案：D
A.must;can B.need;may C.need;can D.can ;may need不用于情态动词的肯定,要用时needn't或need to
4、Write about your favorite musician ( ) actor.答案：C
A.and B.but C.or D.of
(为什么不能用and?） musican 和actor是不同的人 .写出你最喜欢的音乐家或演员
请简略解释一下原因、谢了