21.Biarni was hoping to join his father who was with Eric, but he was blown off course and found himself in an unknown land, ______ he eventually reached Greenland.
A.from how B from where C.from which D.from when
20.All the doctors in the hospital insisted that he_____ badly wounded and that he______ at once. A.should be; be operated on B.were; must be operated on C.was; should be operated D.was; be operated on
19.Over the past decades, mountain ice______ in the Himalayas as a result of global warming.
A.has been decreasing B.had decreased
C.decreased D.is decreasing
18.To our surprise, the fashionable young lady ________ to be a thief. A.found out B.proved out C.put out D.turned out
17.I still remember the days___ I spent ______ with you in Beijing.
A.when; staying B.what; to stay
C.that; staying D.during; to stay
16.In the face of _____ failure, it is vital that we should keep up _____ good state of mind.
A.a; / B./; a C.the; / D./; the
22、在等比数列中,>0,公比,且,又与的等比中项为2。
①求数列的通项公式。
②设,数列前n项和为Sn,求Sn。
③当最大时,求n的值。
21、(本小题12分)
一海轮以20海里/小时的速度向正东航行,它在A点时测得灯塔P在船的北偏东60°方向上,2小时后船到达B点时测得灯塔P在船的北偏东45°方向上。求:
① 船在B点时与灯塔P的距离。
② 已知以点P为圆心,55海里为半径的圆形水城内有暗礁,那么这船继续向正东航行,有无触礁的危险?
湖北省互联网违法和不良信息举报平台 | 网上有害信息举报专区 | 电信诈骗举报专区 | 涉历史虚无主义有害信息举报专区 | 涉企侵权举报专区
违法和不良信息举报电话:027-86699610 举报邮箱:58377363@163.com