(2013·高考江西卷)He wrote a letter________he explained what had happened in the accident.

My mother is ill in hospital. I have to look after her. — .

It is reported that each year Americans ______ the highest percentage of the world’s energy. [ ]

Would you mind __ me how ___ the chemistry problem

They have T-shirts _____ green and black for only $13 _____ the shop.