John has two brothers, but either ____ out of work now. [ ]
A. are
B. is
C. has
D. have
答案:B
目前国内外供应链合作伙伴的选f择方法有很多,当订购数量大、合作伙伴竞争激烈时,企业可采用()。
全口义齿的后牙排列中,若选用非解剖式后牙,则要求上后牙与下后牙的覆盖约为上后牙颊舌径宽度的()
A.1/5
B.1/4
C.1/3
D.3/4
E.1/2