英语等级考试-PETS-写作部分命题规律（二）
● it引导的形式主语句子与其他句型的转换 【例句】
5.he spent 4 hours in doing his homework yesterday.
it took him 4 hours his homework yesterday.
6.it seems that they like pop music.
they to like pop music.
【正确答案】5.to do6.seem
【规律分析】这部分要求了解代词it在句子中的各种用法。it在英语中是个相当活跃的代词，它可以作形式主语、形式宾语和引导强调句等。
● 一些习惯用法的不同表示法 【例句】
7.they have studied english for 20 years.
they began to study english .
8.he went to the class at 9 o’clock.
he didn’t go to the class 9 o’clock.
【正确答案】7.20 years ago8.until
【规律分析】这部分要求掌握英语中一些习惯用法的表达方式。在改写句子时，要求用不同的句型或不同的词表达出相同的意思。
● 词或词组间的互换 【例句】
9.he spent 20 dollars buying this book.
he20 dollars this book.
10.she does well in english.
she is english.
【正确答案】9.paid...for10.good at
【规律分析】这部分考查同义词或词组的替换。有些词虽然意义相近或相同，但往往在用法和结构搭配上有区别，考生应尤其注意。