语从句的省略。

　　If merely drawn on your imagination, the report will not be convincing.

　　假如仅靠你的想象去描绘，报告是不会有说服力的。

　　Once (it is) seen, it will not be forgotten.

　　只要看见了就不会忘记它。

　　[即时演练1]

　　(1)句型转换

　　①Because she was born in a poor family, Nadia had only two years of schooling.

　　→Born in a poor family,_Nadia had only two years of schooling.

　　②Though he is encouraged by his parents, he still has no confidence in overcoming the difficulties.

　　→Encouraged by his parents,_he still has no confidence in overcoming the difficulties.

　　③The patient got off the bed, supported by the nurse.

　　→The patient was supported by the nurse and got off the bed.

　　(2)完成句子

　　①(2016·北京高考改编)Ordered_over_a_week ago, the books are expected to arrive any time now.

　　这些书是一个多星期以前订购的，现在有望随时到货。

　　②Caught_in_a_heavy_rain,_he was all wet.

　　因为淋了一场大雨，所以他全身湿透了。

　　③Watered_more,_these cabbages could have grown better.

　　如果多浇点水，这些大白菜还可以长的更好。

　　④(安徽高考改编)Founded_in_the_early_20th_century,_the school keeps on inspiring children's love of art.

　　这所建于20世纪初期的学校一直激励孩子们对艺术的热爱。

　　2．过去分词作状语需注意的几个问题

　　(1)过去分词、现在分词和不定式作状语的区别：一般说来，过去分词作状语，和句子主语是被动关系；现在分词作状语，和句子主语是主动关系；不定式作状语，一般表示目的。请比较：

　　Seen from the top of the tower, our city looks more beautiful.

　　从塔顶上看，这座城市更漂亮。(主语the city和see之间是被动关系)

　　Seeing from the top of the tower, we can get a wonderful view of our city.

　　从塔顶我们可以饱览城市的美景。(主语we和see之间是主动关系)

To get a wonderful view of our city, we climbed to the top of the tower.