The chairman was about to declare the conference open ____ the lights went all out.
| A．as | B．while | C．then | D．when |
_____ we choose healthy food for our main meals, we probably still need to exercise now and then.
| A．Unless | B．As though | C．Until | D．Even if |
— Do you know something about Kwanzaa?
— It is _____festival celebrating the culture and history of African Americans.
| A．a seven-day | B．a seven-days | C．a seven day | D．seven days |
— How do you find your English teacher?
— She is always full of _____ as though she never knew tiredness.
| A．strength | B．force | C．energy | D．spirit |
— Would you mind if I take the seat next to yours?
— ___________.
| A．Yes, sit down please | B．No, go ahead |
| C．Surely, never mind | D．No, you can’t take it |
_____ you don’t like him is none of my business.
| A．That | B．What | C．Who | D．Whether |