The H1N1 flu spread very quickly at the beginning, __________, many people were ill.

No matter how much time I spend planning a class, little things still _____ go wrong. So I had no perfect class and I reflected all the time.

She devoted herself ______ to her research and it earned her a good reputation in her field. 

In our life, one question that ____ comes up is:“to be or not to be?”

Noise is unpleasant, _____ when you are trying to sleep.