If he ( )tomorrow we'll go skating.快,今天就要!

If he ( )tomorrow we'll go skating.快,今天就要!
If he ( )tomorrow we'll go skating.
快,今天就要!

If he ( )tomorrow we'll go skating.快,今天就要!
If he (is free )tomorrow we'll go skating.
be free表示空闲的意思
翻译：如果他明天空,我们就去滑雪!

comes

is free

If he comes tomorrow we'll go skating.
如果他明天来，我们就去滑冰。（条件状语从句表将来时是，不能用将来时，要用一般现在时）