A terrible earthquake happened ______ the afternoon of March 11th, 2011 in Japan.[ ]

We must find some books ______ our project. [ ]

Attention, please. Sorry to tell you the flight has to be ______because of the heavy snow.

I love junk food very much, but I eat _________ only once a week.

Dad, science is too hard for me.—Oh, dear, if you keep listening ________ in class and do enough exercises, you’ll find it easy.