I can ______ be a teacher. I’m not a very patient person.               

Make sure the gas is turned off after a bath, which would ________ cause danger.

To be an astronaut, you must not only be strong in mind, but also be sound mentally and___.

—Thank god, you finally returned home ________. —You can never imagine how I worried about you when I was told about the terrible accident. 

－Will Daniel come to our gathering? (福建省)－______not,for he is much too busy with his research work.