On a vessel carrying grades A，B，C or D cargoes，enclosed spaces where sources of vapor ignition are normally present shall NOT be segregated from cargo tanks by（）.
1、A band or collar on the top end of a b
A band or collar on the top end of a boom to which the topping lift，midships guy，and outboard guys are secured，is called the（）.Acollar bandBguy bandCpad eye collarDspider band
2、Each open lifeboat carried on a vessel
Each open lifeboat carried on a vessel on an international voyage must have（）.Ahand-propelling gearBa davit span with at least 2 lifelinesCa mast and a sailDa motor
3、设a=2，b=3，c=4，d=5，下列表达式的值是（ ）。 3>2*b Or
设a=2，b=3，c=4，d=5，下列表达式的值是（ ）。 3>2*b Or a=c And bc Or ba+cA1BTrueCFalseD．1
4、Freeing ports on a vessel with soild b
Freeing ports on a vessel with soild bulwards（）.Aprevent stress concentration in the bulwarkBpermit easy jettison of deck cargo in an emergencyCprovide opening through the bulwarks for mooring linesDallow water shipped on deck to flow off rapidly
5、设a=2，b=3，c=4，d=5，表达式3>2*b or a=c an
设a=2，b=3，c=4，d=5，表达式3>2*b or a=c and b<>c or c>d的值是( )A1BtrueCfalseD-1
6、A band or collar on the top end of a b
A band or collar on the top end of a boom which the topping lift, midships guy, and outboard guys are secured, is called the（）.Acollar bandBguy bandCpad eye collarDspider band