先在草稿纸上写出这样的句子：John comes from a large, lower-class family， and he enrolled in college this fall.
我们要把它改进一下：John， who comes from a large， lower-class family， enrolled in college this fall.
草稿句：The dean issued a bulletin， and it said the library would remain open on weekends.
改进句：The issued a bulletin that said the library would remain open on weekends.
草稿句：The house is at the end of the street, and it was designed by a famous architect.
改进句：The house at the end of the street was designed by a famous architect.
草稿句：The guards were fully armed, and they expected trouble.
第一种改进句：Expecting trouble, the guards were fully armed.
第二种改进句：The fully-armed guards expected trouble.
草稿句：Mo Yan is a Chinese novelist, and he won a Nobel Prize.
第一种改进句：A Nobel Prize winner, Mo Yan is a Chinese novelist.
第二种改进句：Mo Yan became the first Chinese novelist who won a Nobel Prize.
草稿句：Mr. Edwards is the manager of the store, and he is a coucilman.
改进句：Mr. Edwards, the manager of the store, is a coucilman.
草稿句：My uncle brought me a gift, and it was a wristwatch.
改进句：My uncle brought me a gift, a wristwatch.
草稿句：Leo thought operating alone was better, and he knew he should not let his colleagues know he had this feeling.
改进句：Leo had enjoyed the independence of his operations, although he was careful to keep that observation to himself.
草稿句：They were sent behind enemy lines. Their tasks were destroying infrastructure, collecting information and carrying out assasinations. They were clandestine raiders.
改进句：Sent behind enemy lines, destroying infrastructure, collecting information, carrying out assasinations, they were clandestine raiders.