民用大中型运输机各操纵面通常采用液压助力操纵，其根本原因是

The （ ） is attached to the back of the （ ） ．

During flight, （ ） can be used to move the nose left and right for desired heading.

During flight, （ ） can be used to move the nose up and down for desired altitude or height.

To initiate a turn, the pilot use the （ ） and （ ） in combination.

Which of the following does not go with all the others?

Which word does not go with all the others?

Which of the following is a primary control system?

Which of the following is an assistant control system?

Which of the following is not part of empennage?

Which word does not go with all the others?