It is widely known that burning coal for electricity is one of the main causes for global warming , but we can’t ignore the cars’ _____ to the greenhouse effect.

Great inventors don’t ________ graduate from famousuniversities. Some didn’t even go to university.

I’d like a wake-up call at 7：00 am, please!—OK，________.

______ many times, he has already known how to do it.

she exercise every day