-----Pay attention to details when solving difficult problems.
------______________.
| A．No,there are no difficult problems. |
| B．Thank you, I will. |
| C．You worry too much |
| D．Don’t mention it. |
----Did you call Sara back ?
----I didn’t need to ,_____ we’ll have a meeting together tonight.
| A．though | B．unless |
| C．because | D．if |
—You look so tired. What’s the matter?
—I was so busy that I didn’t go to bed 12 o’clock last night.
| A．until | B．unless | C．if | D．so |
—Susan, what are the advantages of MP5 players?
—Mom, they are smaller and lighter ______ they can be carried very easily.
| A．unless | B．if | C．until | D．so that |
She is always listening to music ____doing her homework.
| A．as | B．while | C．until | D．though |
Someone called me up in the middle of the night, but they hung up I could answer the phone.
| A．as | B．since | C．until | D．before |