A.off / standby

B.standby / off

C.standby / close

D.close / standby

正确答案：standby / off

2、The abbreviation PPI in the Sperry Collision Avoidance System means（）.

A.plan position indicator

B.plain position indicator

C.plane position indication

D.policy proof of interest

正确答案：plan position indicator

3、Radar makes it possible and much safer for us to sail（）.

A.in dense fog

B.in boisterous weather

C.in the open sea

D.in rivers

正确答案：in dense fog

4、The 10-cm radar as compared to a 3-cm radar of similar specifications will（）.

A.be more suitable for river and harbor navigation

B.provide better range performance on low lying targets during good weather and calm seas

C.have a wider horizontal beam width

D.have more sea return during rough sea conditions

正确答案：have a wider horizontal beam width

5、The ARPA may swap targets when automatically tracking if two targets（）

A.are tracked on reciprocal bearings

B.are tracked at the same range

C.are tracked on the same bearing

D.pass close together

正确答案：pass close together

6、The common way to obtain your ship’s position is（）.

A.keeping a close watch and lookout

B.taking a radar range and bearing

C.observing a radar target and listening to signals

D.keeping a well clear

正确答案：taking a radar range and bearing

7、The radio waves used for radar are very short，only（）long.

A.a few centimeters

B.a few fathoms

C.a few meters

D.a few feet

正确答案：a few centimeters

8、When hitting a solid object such as a ship or an airplane， the radar waves are reflected back（）they came.

A.in the way

B.the way

C.by the way

D.through the path

正确答案：through the path

9、When using a radar in a unstabilized mode， fixes are determined most easily from（）.

A.center bearings

B.tangent bearings

C.ranges

D.objects that are close aboard

正确答案：ranges

10、Which general statement concerning radar is FALSE？

A.raising the antenna height increases the radar range

B.the ability of radar to detect objects is unaffected by weather conditions

C.radar bearing are less accurate than radar range

D.radar should be checked regularly during clear weather to ensure that it is operating properly

正确答案：the ability of radar to detect objects is unaffected by weather conditions