当同学帮你打开了门，你应该说：
A：Thank you
B：You're welcome.
食物的消化和牙齿的咀嚼及舌的搅拌没有关系。（ ）
____ a ____ for me to ____ ____ the old.
My father _____ bus to work and it takes a long time ____ for one.
