酵母菌是第一种“家养微生物”,常用于细胞呼吸的研究。若将酵母菌研磨成匀浆,离心后得上清液(细胞质基质)和沉淀物(含线粒体),把等量的上清液、沉淀物和未曾离心的匀浆分别放入甲、乙、丙三支试管中,各加入等量葡萄糖溶液,然后置于隔绝空气的条件下。下列叙述正确的是 ( )
I think the coffee beans are from Brazil, ________ I'm not completely sure.( )
A.becauseB.sinceC.thoughD.whether
What do we know about the next Olympic Games?
Very ________. The only news is that they won't cancel it.( )
A.a fewB.fewC.a littleD.little
The bush fires in Australia ________ after a few months, leaving millions of animals dead.( )
A.were run outB.run out
C.were put outD.put out
How is your cold, Tom? Did you take the medicine?
Yes, three times a day. But it's getting ________, I suppose. I have a headache today.( )
A.worseB.worstC.betterD.best
You ________ be able to control all the things that happen to you, but you can decide not to be reduced by them.( )
A.need notB.may notC.must notD.should not