题目内容：

We should make full use of whatever happens to us.There is always_______to learn from every experience.
nothing
anything
something
everything
While the plane is taking off or landing,make sure your seat belt________
fastens
is fastens
will fasten
will be fasten
You________worry about their safety.There are old enough to take care of themselves.
mustn't
needn't
can't
wouldn't