[单项选择]It was not until dawn （　） their way out of the forest.
A. when they found
B. that they found
C. did they find
D. that they didn’t find

[单项选择]It was not until dawn_________ their way out of the forest.
A. when they found
B. that they found
C. did they find
D. that they didn’t find

[简答题]Dawn met him well along the way. It was a pleasant uneventful ride

[单项选择]Mr. Smith drove slowly on the way home until he reached the highway, ______ the speed limit was 60 miles an hour.
A. where
B. though
C. when
D. because

[填空题]Many people carry out research in a mistaken way.

[单项选择]

Listening out for whale song is one way that ships can avoid colliding with whales. But what do you do if the whales aren’t singing One answer, developed by researchers in the Canary Islands, is to focus on the way the giant creatures mask the clamour of ocean noise.
No one knows how many whales are killed by ships each year, but collisions are thought to ac- count for up to a third of unnatural deaths. For the northern right whale, this means one or two individuals every year, and with only 300 animals left, that’s an unacceptable loss. There are three global hot spots for whale collisions: northern right whales are at risk in the Atlantic off the east coast of the US and Canada, fin whales in the Mediterranean, and sperm whales off the Canary Islands.
Last year, the Massachusetts-based international Fund for Animal Welfare attached hydro- phones to buoys and successfully listened out for right whale song in the North Atlantic. But since right whales
A. are the only Whales that can sing songs
B. are the only whales capable of masking the clamour of ocean noise
C. provide clues to scientists to study sea currents and waves
D. are on the very verge of distinction