Science is more than a collection of unrelated facts; to be meaningful and valuable, ______ must be arranged to show generalized character.
Everything __________ doing is worthy of __________ well.
It is __________ that she helped other left-behind classmates with their lessons after school.
The __________ teacher thinks it is __________ to devote so much time to his students.
Although it is __________ to watch programs on TV sometimes, I think people shouldn't spend most of the time watching it.
-__________ for you? -How about next Friday?