【单选题】在局部粘膜抗感染中发挥重要作用的Ig是:
【单选题】在局部粘膜抗感染中发挥重要作用的 Ig 是
【单选题】A writer writes a story when he has_________.
A.
had the story as a whole in his mind
B.
understood the development of the story clearly
C.
had some vague idea about an original story in his mind
D.
know how a story is going to end
【单选题】荒漠生态系统因为雨量少,是生态环境最严酷的生态系统之一,雨量一般在( )毫米以下。
【单选题】A writer writes a story when he has ________.
A.
(a) had the story as a whole in his mind
B.
(b) understood the development of the story clearly
C.
(c) had some vague idea about an original story in his mind
D.
(d) known how a story is going to end
【单选题】电动汽油泵中的()可以使发动机熄火后油路内汽油仍保持一定压力,减少了气阻现象,使发动机高温启动容易。