① As the time went on，the weather got worse． 随着时间的推移，天气变得越来越糟糕
② He jumps as he goes along. 他边走边跳。
③The little girls sang as they went． 小姑娘们一边走，一边唱。
四、before引导的时间状语从句表示表示的动作发 生在主句动作之后。 My father booked the room before we arrives. He worked in Hangzhou before he came here.
2. when从句动词为瞬间动词时，不能由while替换。
如：
When he came yesterday, we were playing basketball. 昨天他来时，我们正在打篮球。
三、as引导的时间状语从句表示“当……时”“一 边……一边……”，指主句的动作和从句的动作同时 发生，既可以表示一段时间也可以表示一点时间。
六、as soon as as soon as...可译为一……就……，用来表示 主从句的动作是紧接着发生的。
eg. He will come and see you as soon as he can. 他一有空就来看你。
He rushed home as soon as he got the good news. 他一得到这个好消息就奔回家。
If it rains（从句）， I will stay at home. I’ll go with you if you don’t want to go alone（从句）.
2.如果主句含有must, may, can 等情态动词，从句也要用 一般现在时。
If you drive too fast, you may have an accident. You must stop if the traffic is red. If you finish the homework， you can go home． 如果你作业做完了就可以回家了。 If you want to lose weight you must/should eat less bread.
• 2. when+短暂性动词或延续性动词 • while+延续性动词 • (1)He was doing his homework __w_h_e_n_ I
saw him.
• (2)_W_h_e_n/_w_h_ile_she was singing, we all lost ourselves in her beautiful voice.
如果主句中的谓语动词是瞬时动词时，必须用否定
形式；如果主句中的谓语动词是延续性动词时，用
肯定或否定形式都可以，但表达的意思不同。
He waited until it was 12 o’clock. He didn’t go home until it was 12 o’clock. I worked until he came back. 我工作到他回来为止。 I didn't work until he came back. 他回来我这才开始工作。
• (3)She was cooking __w_h_e_n__ someone knocked at the door.
• 3.进行时+while+进行时
• She was dancing __w__h_il_e___ I was singing
二、when从句的谓语动词可以在主句谓语动作之前、 之后或同时发生；while和as从句的谓语动作必须是 和主句谓语动作同时发生。
(1)_W_h_i_le__ they are waiting for the New Year, they listen to music , sing songs and dance.
(2)_W__h_e_n_ the boy saw his mother, he stopped crying.
If 引导的条件状语 从句Revision_
selfcheck
If 引导条件状语从句
定义：if “如果, 假如” 它引导的句子表示某事发生所需的
条件，即“在…条件下，某事才能发生”，在句子中充当状 语，因此称之为条件状语从句。（ If引导的条件状语从句表 示假如有从句的动作发生，就会有主句动作的发生 ）
时间状语从句
When/while/before/after/until/a s soon as+一个完整的句子构成 “时间状语从句”
注意几点：
一、 when/while 的区别 1.when表示主从句两个动作同时发生或先后发 生。而while表示主从句两个动作同时发生或强 调主句的动作在从句动作进行期间发生。
1．从句动作在主句动作前发生，只用 when。
①When he had finished his homework，he went to
bed at once．
（finished先发生）
②When I arrived at the airport，the guests had
left．
(客人)
（arrived at 后发生）
位置：从句可放在主句之前或之后，但是放在主句之前须有
逗号隔开
eg:如果我有足够的钱，我就去环游世界
If I have enough money, I will travel around the world =I will travel around the world if I have enough money
after引导的时间状语从句所表示的动作发生在主句 动作之后 After they parked their bikes, they went to Tian'an men square. I will call you after I finish the work.
五、 …until… “直到” …not…until…直到……才……

其中 if 是“如果”的意思。
主句一般将来时 ，从句用一般现在时。
构 成
条件从句
主句
时 态
If＋一般现在时 主语＋shall/will+动词原形
例 句
If he comes,
he will take us to the zoo.
用法： 1. 如果主句是一般将来时，从句则用一般现在时。