-have been to...意为“曾经去过某地”，现在已不在那里了，后可接次数，如once，twice，three times等，表示“去过某地几次”，也可和just,never，ever等连用。如:
l have been to Hong Kong twice.我去过香港两次。She has never been to a farm.她从没去过农场。
-lt's really interesting, isn't it?此句是反意疑问句，结构为肯定的陈述句+否定的附加疑问句。
另一种结构为否定的陈述句+肯定的附加疑问句。
如:You didn't go,did you?你没去，对吗?
-put up搭起，张贴
We put up out tents near the lake last weekend.
上周末我们在湖边搭起了帐篷。