语法重点：独立主格结构
。1.原文再现。
This silence was suddenly broken when a large car, with its headlights on and its horn blaring, roared down the arcade.
2.独立主格结构
定义。3.独立主格结构
用法。A．用作时间状语
The work
done(
=After the work had been done), we went home.
工作完成后，我们就回家了。
B.用作条件状语
　Weather
permitting
(=If weather permits), they will go on an outing to the beach tomorrow.
如果天气允许的话，他们将在明天组织一次海滨小游。
C.用作原因状语
An important lecture to be given tomorrow (=
Asan important lecture will be given tomorrow), the professor has to st ...