先天遗传获得的免疫力是()
A.特异性免疫
B.非特异性免疫
C.两者均是
D.两者均否
参考答案:B
The World Wide Web is sometimes jokingly called the World Wide Wait because it ________ be very slow.
A.should
B.must
C.will
D.can
钢中氢气析出会在钢中产生()。