坚持和健全民主集中制原则，是增强党的活力和团结统一的需要。民主集中制是（）。

A. during a rain storm

B. in an explosive atmosphere

C. near a lifeboat station

D. by other than senior rig personnel

What is NOT a requirement for testing the line throwing appliance on a vessel？

A.The appliance should be tested every three months

B.A regular service line should be used when testing

C.A regular projectile should be used when testing

D.An entry about the test must be made in the Official Log Book

In the building of the rail lines, ______.

A．more equipment made in China should be used

B．more imported equipment should be used

C．more exported equipment should be used

D．more equipment used in infrastructure projects should be used

In the building of the rail lines, ______.

A．more equipment made in China should be used

B．more imported equipment should be used

C．more exported equipment should be used

D．more equipment used in infrastructure projects should be used

In the building of the rail lines, ______.

A．more equipment made in China should be used

B．more imported equipment should be used

C．more exported equipment should be used

D．more equipment used in infrastructure projects should be used

In the building of the rail lines, ______.

A．more equipment made in China should be used

B．more imported equipment should be used

C．more exported equipment should be used

D．more equipment used in infrastructure projects should be used