— Is this Tommy’s suitcase?— No, it is not . It is .
I don’t know _____ or not he will come . _______ he comes , I will call you .
The robot needs _______ once a month. And we will check it for you for free.
We didn’t know how to find them because they didn’t tell us _______.
In order _______ his English,he joined an English club.
Don’t make the students _______ this or that . They are busy.