I can't find my purse. I___________ it in the supermarket yesterday, but I'm not sure.
should leave
must have left
might leave
could have left
Jack is a great talker. It's high time that he ________ something instead of just talking.
It is necessary that the government solutions for the problems of air pollution to create a clear environment.
We lost our way in that small village, otherwise we________ more places of interest yesterday.
If we _______ adequate preparations, the conference wouldn’t have been so successful.
Without the development of the Internet, Taobao and Tmall______$ 5.7 billion in sales on 11 November, 2013.