An ________ boy, Li Wen, works hard and gets good grades in his final exam.
eighteen-year-olds
eighteen-year-old
eighteen years old
Everyone in the class studied very hard since no one wanted to _____. A. fall down B fall off C. fall behind D. fall out
No matter how hard it is, just go on and never ____.
While you are doing math exercise, put a calculator(计算器) ____ to help you.
Here you are! This is one of the keys ____ the lock.
I can’t ______ Tom. He is a real idiot(白痴).