there used to be是什么时态

there used to be一般表示过去有某种特性，但是现在没有了，是过去时态。

例句

In the 19th century, there used to be a model of how to be a good person.

在19世纪，曾经有一个关于如何做一个好人的榜样。

There are far more opportunities for young people than there used to be.

现在年轻人的机会比过去多得多。

There used to be some really good stores, but lots of them moved out to the mall.

以前是有一些非常好的商店，但它们很多都搬到购物中心去了。

There used to be an alligator under my bed.

过去曾有条鳄鱼藏在我的床底下。

There used to be a peach tree in the garden, wasn\'t there?

以前在花园里有一棵桃树，对吧？