—Who______ it be that is knocking at the door?
—It ______ be Father, but I’m not sure.
| A．can; must | B．can; may | C．must; can | D．may; must |
______ before bed, cellphones can result in a restless night.
| A．To use | B．Using | C．Used | D．Having used |
Love is_____ makes you smile when you are tired.
| A．that | B．what | C．it | D．which |
How can you imagine the difficulty I had______ to the school life?
| A．to adapt | B．adapt | C．adapting | D．adapted |
The Romany are thought _______ from India.
| A．to have come | B．to come |
| C．to coming | D．to be coming |
—Haven’t seen you for ages! Where have you been?
—I went to Ning Xia and _______ there for a year, teaching as a volunteer.
| A．stayed | B．stay |
| C．had stayed | D．am staying |