501. You'd better look before you leap． 你最好三思而后行。
502. You know what I'm talking about. 我想你知道我在说什么。
503. He has been sick for three weeks． 他已经病了几周了。
504. He inspected the car for defects． 他详细检查车子有无效障。
505. I count you as one of my friends 我把你算作我的一个朋友。!
506. I go to school by bike every day. 我每天骑自行车上学。
507. I have a large collection of CDs. 我收集了很多唱片。
