属于生物可降解性合成高分子囊材的是
A. 聚乳酸
B. 明胶
C. 乙基纤维素
D. 羧甲基纤维素
E. 枸橼酸
Chomsky defines "competence" as the ideal users______ of the rules of his language.
A. instinct
B. knowledge
C. performance
D. realization
According to Dr William Cohn, the artificial heart______.
A. mimics the action of the heart found in humans
B. provides the blood flow of a natural human heart
C. produces pulses by a continuous-pump mechanism
D. uses a small spinning turbine to keep blood flowing at a steady rate
According to Steven, what is the best scenario of the issue？
A. That America, not Israel conducts the attack.
B. That people inside Iran overthrow the government.
C. That Iran gets its way.
D. That America wages a war on Iran and forces a regime change.
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