【单选题】We generally take the convention of safety of life at sea adopted in 1974 as a completely new convention, the reason is _____.
A.
it included the amendments agreed up until that date
B.
it included none of the amendments agreed up until that date
C.
it required two thirds of the Parties’ acceptance for a amendment to enter into force
D.
it included a tacit acceptance procedure
【单选题】下列自动喷水灭火系统中,喷头常开的是()
【单选题】下列自动喷水灭火系统中,喷头常开的的是( )。
【单选题】下列自动喷水灭火系统中,喷头常开的是()
【简答题】证明折射光束的方向是等光程方向.即证明图1-14中 L(A 1 B 1 D 1 )=L(A 2 B 2 D 2 ).
【简答题】如图,已知∠1=∠2,∠A=∠D,证明:∠E=∠C
【单选题】下列自动喷水灭火系统中,喷头常开的的是( )。