Dunlop gave up his veterinary profession soon after he saw the immense possibilities of fitting the pneumatic tires to bicycles and tricycles.
查看答案
Dr. Alexander Fleming was experimenting with a culture of deadly bacteria when he discovered the antibiotic penicillin —a special "mould" he had cultivated all by himself.
A. Y
B. N
C. NG
听力原文: Piglets may be happy wallowing in the mud, but they get a much better start in life if they are nurtured on a warm waterbed. Instead of snuggling up to their mothers for warmth in their cold pigsty and running the risk of being crushed--a common cause of early death--German scientists said waterbeds could be a safer alternative.
When Martin Ziron and researchers at the Institute of Animal Breeding and Genetics in Giessen, Germany tested various heating methods on 1,400 piglets during their first weeks of life, waterbeds won hands down.
"Around 99 percent of the piglets preferred warm waterbeds to any of the alternatives, spending well over half the day lounging about on them and only getting up to feed or play," New Scientist said Wednesday.
The scientists compared the number of injures, which usually occur while scrambling for a feeding position, and the weight gain of the piglets which were provided with plastic plates, foam mats waterbeds, straw or concrete. Piglets on the waterbeds had fewer injuries and gained much more weight than the animals kept on concrete.
According to the magazine, the waterbeds are made from a tough plastic membrane and can be heated from underneath by an electric mat or from above by infrared lamps.
From the passage we know that piglets
A. easily get crushed in the first weeks
B. does not like warm waterbeds in the beginning
C. generally like snuggling up to their mothers for warmth
D. are not happy wallowing in the mud
According to the passage, which of the following statements is TRUE?
A. Many people used cacao seeds in weddings to bless the couple with health.
B. Aztec people used cacao seeds to pay taxes.
C. Spanish people traded with Aztec to get cacao seeds.
D. European people in ancient time liked bitter cacao drink.
M: What's the number? I'll find out if it's available for immediate occupancy.
What are the man and woman doing?
A. Preparing for bed.
B. Walking toward the campus.
C. Looking for a place to live in.
D. Inviting some friends to visit.