An ATC "instruction"（ ）.
A.must be read back in full to the controller and confirmed before becoming effective.
B.is a directive issued by ATC for the purpose of requiring a pilot to take specific action.
C.is the same as an ATC clearance.
正确答案是B
An ATC "instruction"（ ）.
A.must be read back in full to the controller and confirmed before becoming effective.
B.is a directive issued by ATC for the purpose of requiring a pilot to take specific action.
C.is the same as an ATC clearance.
正确答案是B