In the 1983 experiment, human ceils didn't work the way mouse cells did because the former
A. were easier to become aged
B. checked telomerase in dividing
C. had short ends of chromosomes
D. lacked telomeres for cell division
查看答案
What must you do if you use your telecard to make a local call？
A. pay salary
B. pay extra
C. use a card phone
A．whenB．ifC．whichever
A. when
B. if
C. whichever
A．acrossB．intoC．out
A. across
B. into
C. out
A．orB．andC．as
A. or
B. and
C. as
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