我弟弟累的时候，真是让人头疼。

My little brother can ___be ___a real ___pain ___in ___the ___neck when he's tired.

我侄子很可爱，但不如意的时候，他就很烦人。

My nephew is cute, but he can ___be ___a ___pain ___in ___the ___neck when he doesn't get his way.

排长队总是很烦人。

Waiting in long queues always turns out to ___be ___a ___pain ___in ___the ___neck.