Must I use both hands-Yes, you _____.

You’re coughing badly，Martin. Why not give up smoking?—Give up smoking？Easier said than done，Amy. Once you ______ the habit of smoking，it is very hard for you to ______.

Mr. Smith invited me to attend his wedding ceremony, but _____ seriouly ill, I refused his invitation. [ ]

It is generally believed that teaching is_____ it is science[ ]

I will go to the teacher for ________ about my English learning.