— Did he break it accidentally?
— No, ________.
| A．by mistake | B．by chance | C．on purpose | D．with purpose |
The professor told me to start the research right now, ________ I was sure to fall behind.
| A．or | B．so | C．but | D．and |
________ a man's age, he can reduce it several years by wearing a confident smile.
| A．Whichever | B．Whatever |
| C．Whenever | D．However |
After a year, doctors diagnosed him with a disease so rare ________ it affects just one in 8 million children.
| A．after | B．that | C．as | D．since |
________ you need something, please don't hesitate to let me know.
| A．Even though | B．In case |
| C．As though | D．Even if |
One more week, ________ we will accomplish the task better.
| A．or | B．but | C．unless | D．and |