主将if从现

即主语是将来时，从句是一般现在时

无论if在句首或是句中，紧跟着if后的就是从句。

例句：I will travel if I find the treasure.

If the rains heavily this afternoon. Uncil Tom will stay at home.

Don't be worried . He will call you  if he arrives in New York.

when 当......时候

when前主句，when后从句

enough adj.足够的

adv.足够

形e 名

enough在名词前        在形容词，副词后

He has enough time to learn Chinese and he learns it well enough.

Can you see the words on the blackboard clearly enough?