课堂探究

　　1．As a result of this event，a great dust cloud formed in the sky blocking out the sunlight.

　　正因为这一事件，天空中形成了一团巨大的尘云，挡住了阳光。

　　考点：block out挡住，遮住（光线和声音）；忘掉，抹去（不愉快的事）

　　①The volcanic ash blocked out the sun.

　　火山灰挡住了太阳。

　　②An ugly building blocked out the view from the window.

　　一座难看的大楼把窗外的景物遮住了。

　　③I try to block out the unpleasant experience.

　　我尽力去忘记那段不愉快的经历。

　　考点延伸 阅读下列句子，指出block的词组及含义。

　　④Various barricades block off all the main streets of the city.

　　各种路障封锁住了城里所有的主要道路。

　　词组：____________　含义：____________

　　⑤The traffic is very heavy and has begun to block up the streets.

　　交通很拥挤，已经开始把街道阻塞了。

　　词组：____________　含义：____________

　　⑥My nose is blocked up with the cold.

　　由于感冒，我的鼻子不通气。

　　词组：____________　含义：____________

　　⑦We found that a big elephant blocked our way.

　　我们发现一头大象挡住了去路。

　　词组：____________　含义：____________

　　即学即用

　　用block out，block up，block one's way，block off填空

　　（1）You can't leave the village.All the streets are ______.

　　（2）A piece of rock has fallen and ______.We had to stop.

　　（3）Over the years she had tried to ______ that part of her life.

　　（4）This pipe（管子）is ______.There is a piece of wood in it.

　　2．Grammar：主语从句

　　（1）主语从句的定义：在复合句中起主语作用的句子称为主语从句。

　　（2）主语从句在句中作主语，有以下两种结构：

A．主语从句位于句首