to send someone a short message or note
отправить кому-то короткое сообщение (otpravit komu-to korotkoe soobshchenie)
"Please drop me a line when you arrive safely."
"Пожалуйста, отправь мне сообщение, когда безопасно прибудешь." (Pozhaluysta, otprav mnye soobshcheniye, kogda bezopasno pribudesh)
a difficult decision to make
a controversial issue that no one wants to handle
completely flawless or ideal
at the peak of activity or progress
to make a serious mistake or spoil something
to always be ready to help or obey someone