Хэлп!!! Talk on the following points (A. Grammar, B. Word usage):
A. 1. Why is the Present Perfect used in "... as soon as you've called the register”? 2. Why is the Past Perfect Continuous used in ”... who had been crossing and uncrossing his eyes in an ugly manner ...”? 3. Why is the Present Indefinite used in “... till you join us”? and in “If there's anything that puzzles you ...”?

да это жестко оэл-им-это-жиими?ил