I know one of the things _____I was unsure about was _____ hard it would be to climb this mountain.
Every time they met, they ____ talk about former classmates they remembered.
---You seem to have been impressed by his words.---No, not exactly. It was what he did _____ what he said struck me most.
It’s time you changed your attitude ___ your studies, for the time is running out.
In order to catch up with her classmates, _____.
Time means everything, so I won’t have you _______your time like that.