Translate the following sentences.
1.我叔叔已去过美国两次,但我从没去过。
My uncle has been to America twice, but I have never been there.
2.Nick 在哪里?他去了图书馆。
Where is Nick? He has gone to the library.
3.Kitty和爸爸妈妈去了香港,她们一个礼拜之后回来。
Kitty and her parents have gone to Hong Kong. They will be back in a week.