作HLA-Ⅱ类分子分型时,下列哪种方法是应用最广泛且最简便、快捷和精确的方法()
A.SBT
B.PCR-SSO
C.PCR-SSP
D.RFLP
E.PCR-SSCP
参考答案:B
He wants _____English this year.[ ]
A. learn
B. to learn
C. learning
D. learned