An ant was drinking by a small river when it fell in.It made ______ efforts to reach the side，but made no progress at all.

It was not until the end of the meeting_____________.

Many lifestyle patterns do such greatharm to health that they actually speed up ______weakening of the human body

Was it through Mary, _____ was working at a high school, ____ you got to know Tom?

What do you think of your step-mother? —There are some things that are not easy to______, but on the whole she is a good mother.