保安声明应使用()语言写成。
A.船/港都熟悉的语言
B.船/船都熟悉的语言
C.英语、法语、西班牙语
D.以上都可以
参考答案:D
已知等差数列{an}满足:a2=5,a4+a6=22,数列{bn}满足b1+2b2+…
+2n-1bn=nan,设数列{bn}的前n项和为Sn.
(1)求数列{an},{bn}的通项公式;
(2)求满足13<Sn<14的n的集合.
He had an expression of resentment(不高兴), as if Martin___a fool of him.
A.had made
B.makes
C.made
D.would make