There is a set of reduction gears in the carriage.

Comparing with the spur gears, what are the advantages of helical gears? A: Helical gears operate more smoothly and silently. B: High contact ratio and heavier load capability. C: No thrust along gear axis. D: Less sensitive to undercutting

The landing gear consists of the _________ gear and the main gears

In using reduction gears to obtain efficient propeller speeds， （）.

Gear shaping machine can machine the worm gears

Compared with standard spur gears, helical gears have advantages of A: Center distance can be adjusted by changing helix angle B: Contact ratio is big with large load capacity C: Transmission is more steady D: Axial force exist

A set of are installed to control the speed and direction of the vehicle. A: wheels B: gears C: gea D: wheel

A set of _____ are installed to control the speed and direction of the vehicle. A: arrays B: gears C: giants D: aliens

The linear motion of a diesel engine piston is converted to the rotary motion required to drive gears， propeller shafts， and generators by the （）.

Is it really necessary to wear all these protective gears? 真的有必要穿戴所有这些防护用具吗?