When Helen saw his tutor nod ________ to her, she calmed down and went on with her performance

_______ is your music teacher— Ms. Xie. I like her classes very much.

With the help of the smart phones, you ____ video chat with your friends on the phone.

I think students should have mobile phones to call their parents.–_______ . They often use them to play game instead.

hing ________, the oceans will turn into fishdeserts.