数列{an}中,a n+1=a n+2﹣an,a1=2,a2=5,则a5为 [ ]
A.﹣3
B.﹣11
C.﹣5
D.19
答案:D
How much did the computer _____ you? And how much time do you _____ on it every day? [ ]
A. take; cost
B. spend; pay
C. cost; spend
D. pay; take
男,47岁,腹泻、体重下降,伴有重症肌无力,结合胸片和CT,最可能的诊断是()
A.胸腺增生
B.胸腺瘤
C.淋巴瘤
D.纵隔血肿
E.错构瘤