Li Fang is very busy,__________she’s always helping others with their lessons.
Happy birthday, Alice! So you have _____ twenty-one already.
The computer was used in teaching. As a result, not only _____, but students became more interested in the lessons.
Teachers have to constantly update their knowledge in order to maintain their professional(专业的)_______.
Everything comes with _____ price; there is no such _____ thing as a free lunch in the world.
The most important thing_______we should pay attention to is the thing_______I have said.