__________ many times, she still can't remember it.
There is an increasing concern _____________ about Ebola infection. Every country has taken necessary measures to prevent it.
In the noisy crowd, I had to raise my voice to make myself ___________.
As we can see, Peter is very happy, so he___________ have passed the exam. After all, it’s not difficult at all.
—Is Bob still a volunteer?—No, but he _____. He worked for the 2008 Beijing Olympic Games.
You’d better _______ because I’m busy writing a letter to my parents.