Some English questions ,急····

Some English questions ,急····
选出与划线部分相同意思的词语
1.—Are there a number of students canspeak french?
No,there aren't.(a number of 画线）
A .lots of B a lot C.many D much.
lots of 即可修饰不可数与可数,那many 和lots of 不都是可以一样的替换吗?那选择哪一个呢?
2.When are they getting back to our city
A.giving back B.back C.returning D.taking back
(对 getting back 画线提问）
Mary's babysitting her aunt's baby at home.
可化为Mary is babysitting her aunt's baby at home.那在这句中,Mary is 是可替换Mary's
There is a boy and a girl.
这句话是对的吧?是不是因为就近原则?
改为感叹句：Mike is working hard.
_____ ______ Mike is working.
改为同义句：We hope they can come here.
We _______ _______ to come here.