等比数列 $\left\{a_{n}\right\}$ 的各项为正数, 且 $a_{5} a_{6}+a_{4} a_{7}=18$, 则 $\log _{3} a_{1}+\log _{3} a_{2}+\cdots+\log _{3} a_{10}=(\quad)$
解析: $a_{5} a_{6}+a_{4} a_{7}=18 \therefore a_{5} a_{6}=9$,

$\log _{3} a_{1}+\log _{3} a_{2}+\cdots+\log _{3} a_{10}=\log _{3}\left(a_{1} a_{2} \cdots a_{10}\right)$

$=\log _{3}\left(a_{5} a_{6}\right)^{5}=5 \log _{3} 9=10$.