I’ve listened to Professor Smith’s talk about medicine,but I still haven’t got a good understanding of its key _________.
When the news came _______ the war broke out, he decided to serve in the army.
He came all the way to China for learning it better ______ for making money.
Only when I left my parents for Italy ______ how much I loved them.
_____ the days and months went by, things were getting worse and worse.
My uncle’s house in the downtown area is much smaller than ours, but it is twice ______expensive.