祈使句， and 陈述句: 在这里祈使句相当于if 引导的条件状语从句(但此时去掉and)。
Give blood ( if you can )and many lives will be saved.
还可以用简短的形式表示，即省略动词。
Give me one more hour, and I’ll get the work finished.(祈使句)
==One more hour, and I’ll get the work finished.(名词短语)
== If you give me one more hour, I’ll get the work finished.(if条件句)
==If I am given one more hour, I’ll get the work finished.
== Given one more hour, I’ll get the work finished.
More effort, and you will succeed.
Another attempt, and you will get it.
One more minute, and the patient would have bled to death.
祈使句， or 陈述句
Listen to the teacher carefully in class, or you can’t catch what he is saying.
Let’s keep to the point，or we ______ any decisions.
A will never reach B have never reached
C never reach D never reached
注意：
祈使句 and 陈述句结构；祈使句 or 陈述句结构，这里的祈使句相当于if条件句。如：
1、 Work hard and you will make progress. = If you work hard, you’ll make progress.
（肯定的条件）
2、Hurry up, or you will be late. = If you don’t hurry up, you will be late.（否定的条件）
训练：
Try harder ________ you will win a ticket for the 2008 Olympic Games．
A.but
B.and
C.or
D.so
答案 :
B
Study hard, ________ you will make great progress．
A.and
B.or
C.or else
D.otherwise
答案 :
A
