We've had to alter some of our plans是完成时态嘛?\x08怎样分析句子结构呢?为什么不...We've had to alter some of our plans是完成时态嘛?\x08怎样分析句子结构呢?为什么不这样说We have to alter some of our plans嘛?

We've had to alter some of our plans是完成时态嘛?\x08怎样分析句子结构呢?为什么不...We've had to alter some of our plans是完成时态嘛?\x08怎样分析句子结构呢?为什么不这样说We have to alter some of our plans嘛?
We've had to alter some of our plans是完成时态嘛?\x08怎样分析句子结构呢?为什么不...
We've had to alter some of our plans是完成时态嘛?\x08怎样分析句子结构呢?为什么不这样说We have to alter some of our plans嘛?这样不更简明?

We've had to alter some of our plans是完成时态嘛?\x08怎样分析句子结构呢?为什么不...We've had to alter some of our plans是完成时态嘛?\x08怎样分析句子结构呢?为什么不这样说We have to alter some of our plans嘛?
完成时表示的动作是过去发生的,对现在产生了影响.这个句子的意思是,我们已经修改了部分计划.是过去发生的动作.
第二个句子,翻译为我们不得不修改部分计划.是将要发生的.
两个句子表达的意思不同.