单项选择题
You can swing the derrick to starboard side or port side. But do not exceed （）for the union purchase.
A.120° B.90° C.60° D.100°
单项选择题 When the derrick is lowered, the guys must be （）.
单项选择题 When the derrick is topped, the guys must be （）.
单项选择题 Do you want the derrick adjusted （）?
