等比数列{an}的各项均为正数，且a5a6+a4a7=18，则log3a1+lo_爱下问搜题

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问题选择题

等比数列{a_n}的各项均为正数，且a₅a₆+a₄a₇=18，则log₃a₁+log₃a₂+…log₃a₁₀=（　　）

A．12

B．10

C．8

D．2+log₃5

答案

答案：B

填空题

Questions 14-18

·Using the information in the text, complete each sentence 14-18, with a word or phrase from the list below.
·For each sentence (14-18), mark one letter (A-G) on the Answer Sheet.
·Do not mark any letter twice.

A. best preserved in the word
B. completely Forbidden
C. Palace Museum
D. all over the country
E. 961m long
F. 8704m long
G. unknown

The building material needed of the Forbidden City were from ______.

选择题

用起重机将质量为m的重物匀速竖直提起一段距离，那么作用在物体上的各个力的做功情况是（　　）

A．重力做正功，拉力做负功

B．重力做正功，拉力做正功

C．重力做负功，拉力做负功

D．重力做负功，拉力做正功