Blue whales are the largest animals in the world. But they are amazing _______ because of their huge size, but their slow heartbeat.
For the first time , scientists have researched the _______ of a blue whale. They found _______ when blue whales dive (潜水) for food, their heart rates (心率) are as _______ as 2 beats per (每) minute (bpm). Scientists used to _______ that their diving heart rate was 15 bpm. When the whales go to the ocean’s _______ to breathe, their heart rate is between 25 and 37 bpm.
Usually, the larger an animal is, _______ its heart beats, since it takes more time to pump (输送) blood around _______ body. Shrews, the smallest mammals (哺乳动物), have a heart rate of up to 1,000 bpm. Humans usually stay between 60 and 100 bpm.
_______ slowing their heart rate, blue whales can send more blood to the muscles (肌肉) that they use ________. These muscles become stronger, allowing the whales to dive for longer periods of time.
1.A.neither B.either C.not only D.although
2.A.heartbeat B.body size C.diving D.food
3.A.it B.that C.once D.if
4.A.many B.little C.fast D.slow
5.A.regard B.expect C.think D.doubt
6.A.bottom B.surface C.center D.side
7.A.the slower B.slower C.the faster D.faster
8.A.it’s B.its C.his D.her
9.A.By B.In C.On D.At
10.A.to pump blood B.to eat C.to breathe D.to dive
— You look down! What’ s up?
— ________.
A.I’m watching a sitcom B.My mom is ill C.I just finished high school
—________ an amusement center, some restaurants and hundreds of stores in the shopping mall.
—Wow, it’s amazing. I will go next week.
A.There is B.There are C.There will be
—Why don’t you find some workers to repair the machines?
—Well, ________ of them want to do such a low-paid job.
A.a few B.few C.some
—We’d better ask the local people when we’ll get to the next town.
—We did. But nobody could say ________ it would take.
A.how often B.how far C.how long
—What do you know about the earthquake happened in the morning?
—The wounded people ________ to the hospital in time.
A.are brought B.were brought C.will be brought