Поставьте правильное грамматическое время.
how long they (to know) each other?
tom cant find his key. hes afraid he (to lose) it?
my aunt (to go) to Canada next summer.

ответ: How long have they known each other?

Допустим вариант и просто - know each other

Tom can`t find his key. He`s afraid he`s lost it.

(когда говорим о результате без привязки ко моменту времени - время Present Perfect)

My aunt will go to Canada

Объяснение: