内因子缺乏将导致
A.再生障碍性贫血B.缺铁性贫血C.恶性贫血D.巨幼红细胞性贫血E.臼型地中海贫血
参考答案:D
We have classes _____ Monday _____ Friday.[ ]
A. at, to
B. from, to
C. from, for
D. on, on
I found _________difficult to work out the problem.
A it’s B this C that D it