若数列{a_n}的前n项和S_n=n²+1 则a₁+a₉等于（　　）

青蛙属于两栖动物，下列有关青蛙生殖和发育的叙述，不正确的是（    ）

完形填空

　When time comes to December in England, there  1  usually lots of snowstorms. Though they can often  2  traffic accidents,  3  local people and drivers are quite  4  terrible weather. However, to everyone's  5  , a special “apple rain”  6  in Coventry  7 December 12, 2011. “It's 8 thing I've met all my life! ” said Mr Turner, a  9  man who has lived in the city for more than 50 years.

    It was about the rush hour in the evening, and many people were just  10 in the street when the apples  11  fell down without warning. Some people thought the apples might fall from a plane, while  12  regarded it  13 a trick from naughty children.

The UK Met Office(英国气象局) said on 14th that it could be the result of cyclones(气旋) in the storm. It  14  that some storms can carry things like apples away as  15  as 100 miles (about 161 kilometers).

如图，⊙O是△ABC的外接圆，∠OCB=30°，则∠A的度数等于(       )