In summer milk will quickly go bad_____ it is put into a fridge.
My cousin Mary was born ___ a singing voice.A.from B.in C.with
--How do you learn English?--I learn English ___ practicing conversations with friends.A.on B.by C.in
—You look very worried. ________ ?—My mother suddenly got ill yesterday.
I found _____ necessary to save energy and protect the environment.
In our city, _____ middle school students want to work as a teacher in the future.