This sentence is too hard _____________ me understand.-Don’t worry. Let me explain it you. [ ]

Do not give up! Perhaps ________ tough task needs more of your effort. — I won’t. I’ll have ________ second try anyway.

I’m not a little tired today after giving the room a thorough cleaning and I have never had_________today.

It’s too dark here. Please __ the light.

Tom is ____ late for school. He goes to school on time(准时) every day.