—How did you save the drowning girl?—By using a _______.
____________ the Roman numerals, the Arabic numbers are rather simple to use.
___________ a reply, he decided to write again.
This is the material ________ in the laboratory tomorrow morning.
.I’ll go to bed now. I am not ________ up late.
.The old man said the accident ___________ carless driving, so a lot of money should be paid by the driver.