句型转换 1,what you will do is of great importance强调主语从句

二楼答案有误,正确说法是：
1. It is what you will do that is of great importance.
2. It is only when one is ill that one realizes the value of health.
3. It was Tom whom/that we invited to give us a lecture last week.
另附：强调句型的结构如下：
It is/was + 被强调部分 + that(如果被强调部分为人时,还可以使用who/whom) + 句子未被强调部分.
其最大特点是：如果取得it is/was和引导词that/who/whom后,剩下部分就是一个完整的句子（有时候需要调整前后句序）.