Mr Smith is strict __________ us __________ our studies.
Mark needs to learn Chinese _______ his company is opening a branch in Beijing.
_________I have to give a speech, I get extremely nervous before I start.
In the global economy, a new drug for cancer, ______ it is discovered, will create many economic possibilities around the world.
Anyone, once ____ positive for H7N9 flu virus, will receive free medical treatment from our government.
(2013·北京卷)I took my driving license with me on holiday, I wanted to hire a car.