词义辨析 journey/tour/travel/trip这些名词均含"旅行"之意。

journey: 最普通用词，侧重指时间较长、距离较远的单程陆上旅行，也指水上或空中的旅行。

tour: 指最后返回出发地，旅途中有停留游览点，距离可长可短，目的各异的周游或巡行。

travel: 泛指旅行的行为而不指某次具体的旅行，多指到远方作长期旅行，不强调直接目的地，单、复数均可用。

trip: 普通用词，口语多用，常指为公务或游玩作的较短暂的旅行。

5.keep...to oneself

If people have problems, they should try to keep them to themselves.

如果人们遇到问题，他们应尽量保密。

keep...to oneself意为"保守秘密"，keep后接名词或代词作宾语，themselves是反身代词，作宾语补足语或同位语。如：

Women often keep their ages to themselves. 妇女往往对她们的年龄保密。

He kept the news to himself. 他没告诉任何人这条消息。

6.unless

Unless we talk to someone, we'll certainly feel worse.

如果我们不跟别人说，我们肯定觉得很难受。

conj. Unless 除非，如果不，后接从句，意思相当于if not，也遵循"主将从现"原则，如：

You won't catch the bus unless you run. 你如果不跑着去，就赶不上公共汽车。

I'm not happy unless I ride or drive every day.只有每天骑车或开车我才会开心。

7.certainly

Unless we talk to someone, we'll certainly feel worse.如果我们不跟别人说，我们肯定觉得很难受。

adv. certainly 肯定，一定；当然，当然可以。主要用来对真实的确实发生事情的强调。如：

He certainly knows the answer. 他肯定知道答案。

注意：certainly在句中位置灵活，可放在系动词和助动词之后，也可置于谓语动词前。如：

He will certainly be there. 他一定会去。

8.understanding

In the end, she talked to her parents and they were really understanding.

最后，她跟她父母说了，并且他们理解她。

adj. understanding 善解人意的，体贴的，作定语或表语。如：

Luckily, I have a very understanding boss. 幸运的是，我有一个通情达理的老板。

n. understanding 明白，了解，协定，协议。如：

This is out of a child's understanding. 这是孩子所不能理解的。

make mistakes意为"犯错误"。Mistake是可数名词，意为"错误，失误"。如：

He often makes some mistakes in his maths homework. 在数学作业中，他经常犯一些错误。

by mistake 错误地

She put salt into her tea by mistake.她误把盐放进茶里去了。

9.solve

We would always try to solve them. 我们应该总是尽力去解决它们。

vt. solve 解决，解答，后接名词或代词。

（过去式:solved 过去分词:solved 现在分词:solving 第三人称单数:solves）

He is good at solving difficult problems. 他擅长解决难题。

I dreamed up a plan to solve both problems at once. 我想出了一个方案，可以同时解决两个问题。