When anaerobic bacteria convert the sewage to an inert sludge, .
A.no oxygen is needed
B.oxygen is necessary
C.oxygen is given off
D.no gas is produced
第1题
Anaerobic adhesives set up into hard, strong adhesives when ______.
A.The two parts of resin and catalyst are mixed
B.Squeezed into thin joints which block the oxygen
C.The solvents evaporate or penetrate porous adherends
D.The heat source is removed
第2题
A) Hot-melt adhesives
B) Loss-of solvent adhesives
C) Anaerobic adhesives
D) Two-part mix adhesives
第3题
听力原文: Tears keep your eyes wet and they also contain substance that kills certain bacteria so it can't infect your eyes. Give up your tears and you lose this on-the-spot defense. Another thing you couldn't do without your tears is cry from joy, anger or sadness. Humans are the only animals that produce tears hi response to emotions. And most people say a good cry makes them feel better. That has led many scientists to believe that crying is an adaptive response to stress, that it somehow helps us cope with emotional situations. Tear researcher William Frey is trying to find out how it happens.
"One possibility," be says, "is that tears discharge certain chemicals from your body, chemicals that build up during stress. When people talk about crying it out, I think that might actually be what they are doing." He says. If Frey is right, how do you think not crying affects those who tend to "hold it in"? Boys, for example, cry only about a quarter as often as girls once they reach their teenage years. And we all cry a lot less now than we did as babies. Could It possibly be that we face less stress? Maybe we've found other ways to deal with it. Or maybe we just feel embarrassed.
(33)
A.To keep your eyes a bit drier.
B.To protect your eyes from infection,
C.To cry for your sadness only.
D.To conceal your happiness.
第7题
A、aerobic
B、anaerobic and autotrophic
C、anaerobic and heterotrophic
D、auxotrophic
E、autotrophic
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