13、have some problems(in) doing sth 做、、有问题

the answer to the question/problem 问题的答案

12、the top of a mountain 山顶

11、the day after tomorrow后天　 the day before yesterday前天

10、go on /have a picnic 去野餐

9、the fifth lesson第五课

8、many different kinds of许多不同种类的　 all kinds of各种各样

7、be good at=do well in +V-ing/sth 擅长做、、、

6、agree with sb同意某人　 agree to do sth同意做、、、

5、go fishing/hiking/boating/shopping/skating/swimming

4、Let’s discuss it.让我们讨论一下