7 、 The force which holds the solar system together is called gravitation. → The force holding the solar system together is called gravitation.
8 、 A medical drug would not be effective if it was kept too long. → The medical drug would not be effective if kept too long.
9 、 It happened that he was away at that time. → He happened to be away at that time.
第五、多用对句法 。
尽量用同类型的句子成份把同等地位的概念排列着,使外表划一。例如:
10、 Anyone wishing to write effectively must learn to think about points logically, organize ideas coherently, and express thoughts explicitly.
11 、 The teacher told a foreign scholar that he should be familiar with the local environment, that he needed to have a room with good lighting, and that he must arrange specific hours for self-study.