I hope everyone can care about ______ the environment and stop ______ things.
--- How do you study English?---I study English talking with foreign students
--- My son seldom has breakfast.--- It is unhealthy habit.You must ask him to change it.
I am wondering ________ my invitation and join me for the trip to Hainan this summer.
They have discussed the plan for some hours but no agreement ________.
I had waited for several weeks without __________ Sam so I e-mailed him again.