It is not until/till ... that /who/whom ...
It was not until/till the professor came that they began the test. ç´å°è¿ä½æææ¥äºï¼ä»ä»¬æå¼å§æµè¯ã
2. Is it +被强è°é¨å+ that/who/whom...?
Is it on the desk that you have left the keyï¼ä½ æé¥åå¿å¨ä¹¦æ¡ä¸äºåï¼
Is it Tom that / who is knocking at the door?æ¯æ±¤å§å¨æ²é¨åï¼
3. çé®è¯+is it + that/who/whom...?
How is it that you are still here? ä½ ä¸ºä»ä¹è¿å¨è¿å¿ï¼
What is it that has brought you hereï¼æ¯ä»ä¹äºæä½ å¸¦å°è¿éåï¼
Why is it that you are late?ä½ æ¯ä»ä¹åå è¿å°çå¢ï¼