你知道昨天你们教室里有5个钱包吗？ 翻译为：DO you know that there was five wallets in you classroom yesterday? 为什么要用 do you know 不用 Did you know``

My mother hopes that we can buy a big house next year.可以用将来时吗My mother hopes that we will buy a big house next year.

```that we can buy a big house next year.为什么可以用can buy