What word did the pilot say after receiving the order?

means "copy"

However, the pilot asked to repeat the instructions after receiving them for the sender's confirmation.

these are all standard radio communication rules.

zxpzcy downstairs reminded me, and I forgot about roger. Give him the score, not me.

In fact, the standard civil aviation terms are as follows:

roger: Air China 157, maintain the descending altitude of 9, establish the blind descending report

Aircraft: descend altitude of 9, establish the blind descending report, Air China 157

didn't understand it, or received and copied the word "received",

In other airlines.