下列哪种标志不出现于B细胞表面( )
A.MHC-Ⅰ类分子B.MHC-ⅡC.PWM-RD.C3b受体E.CD2分子
参考答案:E
—Students should try to do a little studying every evening throughout the term, rather than study all night
during the week before the exam.
—Exactly. ____________.[ ]
A. Practice makes perfect
B. The early bird catches the worm
C. Slow but sure wins the race
D. Delays are dangerous
现阶段的吊顶可分为哪些类型?