67. swam – swim 考查动词时态。文章讲述的是通常的惯例，故用一般现在时。　　

66. 正确　 经分析本句正确。　

85．去掉第二个and考查句子结构的分析。本句前面是if引导的条件句，后面是主句，所以去掉and。

I

[2010·成都三诊]

Usually most divers don’t go very deep. Mainly they dive to　　　　　　　 66．　　　 　

a depth of about 20 meter. Then they swam around as they slowly　　　　　 67．　　　 　

return to the surface. Everyone wants to dive must first have diving 　　　 68．　　　 　

lessons. There are few dangers that you have to learn about. For one　　　 69．　　　 　

thing, you might have problems with its air bottle. A diver must　　　　　　　　 70．　　　 　

know how the equipment works and is able to recognize possible　　　　　　　 71．　　　 　

problem. There are also dangerous types of fish that you must look　　　　　 72．　　　 　

out for. You must be familiar to the environment you’ll be diving　　　　　　　　 73．　　　 　

in. Before you go on a dive, make sure you know that what you are 　　　　 74．　　　 　

getting into. Diving may look easily, but if you don’t have the　　　　　　　　　　　 75．　　　 　

necessary training, it can be both difficult and dangerous.　　　　　　　　　　　　　

84．protect改为protecting 考查介词的用法。因为pay attention to中的to是介词，故用动名词。

83．it改为that　 考查代词的用法。此处that用于比较句型，因其后有定语in the city。

82．crop改为crops　 考查名词的单复数。根据语意应用复数形式。

81．come前加that或come改为coming 考查句子结构的分析。本句的谓语动词是are，所以come需以分词作定语或作定语从句的谓语的形式出现。

80．正确　 经分析本句正确。

79．noisy改为noise / noises 考查形容词和名词的用法区别。此处名词作with的宾语，故用noise。

78．Besides改为However　 考查副词的用法。根据文意前面为优势后为劣势，故表转折用however。