She ____________ so happy today. [ ]
A. is
B. am
C. are
答案:A
已知数列{an},{bn}分别为等差和等比数列,且a1=1,d>0,a2=b2,a5=b3,a14=b4(n∈N*).
(Ⅰ)求{an},{bn}的通项公式;
(Ⅱ)设cn=an•bn,求数列{cn}的前n项和.
原发性肝癌肝区疼痛特点是
A.烧灼样疼痛
B.持续性胀痛
C.阵发性绞痛
D.刀割样疼痛
E.间歇性隐痛