519. The play may begin at any moment． 戏随时都有可能开始。

518. The boy was too nervous to speak． 那男孩紧张得说不出话来。

517. The book you ask for is sold out． 你要的那本书已经售完了。

516. That is my idea about friendship． 这是我关于友谊的看法。

515. Susan is going to finish college． 苏珊将完成大学学业。

514. Patience is a mark of confidence. 耐心是自信心的一种表现。

513. Let's divide the cake into three． 我们将蛋糕分成三份吧。

512. It's very kind of you to help me． 你帮助我真是太好了。

511. It's a secret between you and me. 这是你我之间的秘密。

510. Is there any sugar in the bottle? 瓶子里还有糖吗?