Others argue that since the earth has endured a long string of ice ages in the last two millionto three million years, any warming is ________ to be temporary.
When he suddenly ________ up the subject of genetic engineering, there was an embarrassedsilence.
If you want to find a decent location for your own home, ________ Mr. Smith for advice.
Wemust______thattheexperimentiscontrolledasrigidlyaspossible.