I have to go on,________difficulties I will meet.
---Is Medicine a science? ---Well, nowadays, most doctors recognize that medicine is ____ it is a science.
---The book is borrowed from the library. You ____ your children touch it with their dirty hands. ---Sorry.
____ is none of your business.
---Why are the four students so happy? ---_______ in the science competition, they are awarded prize money totaling $20,000.
---We’ve seen many more days of blue skies recently. ---True. But back in 1998, ________ Beijing started its “Defending the Blue Sky” program, the city only ________ about 100 days a year.