Question

Look at... 要注意什么是不可省略的.如果后面有跟句子,句子一定是什么时态?

Answer 1

要注意at不能省略,因为有的特殊句型会把look 与 at分开,所以这是要注意的.

而at是介词,因此后面不能跟句子,如果加的话,应该是加名词或者动名词,或者是短语,再或者是用定语（从句）修饰的名词.

例如：Look at those boys who are playing football,they.

OR :Look at those playing boys,they...