关于强调句型我想问一下,下面的两个句子为什么不是强调句1 It is a question that needs car

1.强调句型的结构是：It is/was + 被强调部分 + who/whom/that + 句子未被强调部分.
其最大特点是：去掉It is/was和引导词who/whom/that后,剩下部分是一个完整的句子（大多时候需要调整句序）.
2.这两个句子的确都不是强调句型,原因如下：
1）It is a question that needs careful consideration.
去掉It is和引导词that之后,剩下句子为：A question needs careful consideration.
此句看似一个完整且正确的句子,其实不然.
因为翻译为“一个问题需要仔细的考虑”后句意不通.
应该把主语的不定冠词a改成the才行,即正确的句子应该是：
The/This/That question needs careful consideration.
所以此句是一个含有that引导的定语从句的句子.
2） It was five o'clock when the plane landed at the airport.
这个句子明显不是强调句型,因为强调句型的引导词不可能是when.
如果该句如下修改的话,则才是强调句型：
It was at five o'clock that the plane landed at the airport.
去掉It was和that之后,句子还原为：
The plane landed at the airport at five o'clock.

2不是

1:去掉it is that 原句不成立，就不是强调句．
2无it is that 结构