I get up early______I can go to school on time.

regularexercise is very important.It’s never a good idea to exercisetoo close to bedmme.

Rock-climbing is a breathtaking activity, very popular nationwide among young people, ______ cooperation as well as courage plays an important role.

We can’t get the machine to run. There must be ______ with it.

Nuclear science should be developed to benefit the people _____ harm them[ ]