What’s up? You look worried.Well,I_____on the problem for 5 hours but I haven’t got a single clue

Look! The girl __________ long hair is building a snowman. Is she Sandy — It __________ be her. I’m not sure.

________ back to China, all the staff who had worked in Libya strongly felt that our country is very powerful.[ ]

About ____of the students in Grade Nine this year were born in the_____.

Should I lock the lab before I go home—_ _．I’ll check it myself later．