已知数列{an}的前n项和Sn=n（n+2），数列{bn}的前n项和为Tn，且有

电子台秤在使用前，应先高调整（）使水平泡内的水泡处于中心位置。

对支气管和支气管树的描述，正确的是（）。

A.主支气管再分为次级支气管，称为肺叶支气管

B.左肺有上、中、下3叶支气管

C.右肺有上、下2叶支气管

D.肺叶支气管的分支呈树状，称支气管树

E.以上都错

个人合伙的财产属于（）。

A.合伙人共有

B.合伙人分别所有

C.部分共有，部分分别所有

D.出资属于个人所有，经营积累的财产属于共同所有

The ABC Bank Irrevocable documentary credit Number: LC123-258866 Date: August 24,1999 Date and place of expiry : October 30, 1999 China Advising bank: Bank of China Beneficiary: China XYZ import and export corp. Applicant: UVW corporation. Amount: USD52,500 (Say U.S Dollars fifty two thousand five hundred only) We hereby issue irrevocable documentary credit which is available with: Any bank By negotiation of beneficiary’s drafts at sight For full invoice value Drawn on the ABC bank Partial shipments: Not allowed Transshipment: Not allowed Shipment from: Shanghai To: Tokyo Japan At the latest: October 15, 1999 Following documents required: +Signed commercial invoice in three copies +Full set of clean on board ocean bill of lading +Weight certificate in two copies Covering: 100 metric tons (5PCT MOL) of XY chemical in drums at USD 500 per M/T. Special instructions: Insurance to be effected by buyer. Instructions to advising bank: Please advise this credit to the beneficiary We hereby undertake that drawers, endorsers in compliance with the terms of this credit will be duly honored upon presentation to the drawee bank. Authorized signature 一、根据上述信用证，回答下列问题

装船期限

在我国，出具不可抗力事故发生证明的是（）。

A.对外经济贸易合作部

B.中国国际贸易促进委员会

C.海关

D.商检局