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【单选题】
关于细胞因子的特点正确的是A.
细胞因子是由细胞活化后产生的
B.
单一细胞因子可具有多种生物学活性
C.
细胞因子可以自分泌、旁分泌、内分泌三种方式发挥作用
D.
细胞因子的作用不是孤立存在的
E.
以上均正确
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【简答题】A．is B．was C．has been D．is being
【简答题】A. has B. being C. was D. is
【简答题】For it is 'everybody' , a whole society, A(which), has identified B(being) feminine with C(caring about) how one looks. D(Given) these-stereotypes, it is no wonder that beauty enjoys, at best, a rathe...
【简答题】A．is B．was C．has been D．is being
【单选题】The silence of the library _____ only by the sound of pages being turned over.
A.
has been broken
B.
was broken
C.
broke
D.
breaks
【判断题】Being a laywer has been considered as one of the most ideal and stable profession in China.
A.
正确
B.
错误
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