Throughout the history,the mosequito has been not only a nuisance but a killer,carrying some of the deadliest diseases known to man.帮忙改个错,就一个错.
问题描述：
Throughout the history,the mosequito has been not only a nuisance but a killer,carrying some of the deadliest diseases known to man.
帮忙改个错,就一个错.
答
把been放到not only 的后面
答
...but also a killer.