There will not be enough space to _____ the earth in the future. [ ]

I don’t know he tomorrow. I think if he, I’ll go to see him.

I’ve promised to help you and I’ll _____ my word.

Is that Kate’s car?–It ______be hers. She has just gone for a meeting.

第一部分：单项选择—Make sure you have turned off the air conditioners before going out.—_______________.