Section ⅢGrammar - 动词不定式和but＋不定式

　　语法图解

　　 探究发现

　　①Experts hope to learn more about the movement of thunderstorms.

　　②There was nothing to be done.

　　③The storms sometimes continue all day and traffic moves very slowly because the thick dust makes it difficult to see.

　　④When a sandstorm arrives in the city, weather experts advise people not to go out.

　　⑤It is difficult to breathe and the dust makes me ill.

　　⑥To prevent it coming nearer, the government is planting trees.

　　⑦My job is to teach.

　　⑧I can do nothing but wait at home.

　　⑨She has no choice but to give in.

　　 [我的发现]

　　(1)①～⑦句中，不定式在句中分别充当宾语、定语、宾语、宾语补足语、主语、状语和表语。③句中，it为形式宾语；

　　⑤句中，it为形式主语。

(2)由④句可知，不定式的否定式为not_to_do。由②句可知，不定式的被动式为to_be_done。