When comparing twin screw tug to single-screw tugs,which statement about a twin-screw tug
A. If one engine fails,you do not lose control of the tow
B. It is more maneuverable
C. It develops more bollard pull for the same horsepower
D. It is generally subject to more propeller damage from debris in the water
查看答案
鸟类左右心室已有了分隔,因此,鸟类的血液循环已属于完全的双循环。()
鸭嘴兽为卵生的哺乳动物,在分类上属于后兽亚纲。()