The students in a certain physical education class are on either the basketball team or the tennis team, are on both these teams, or are not on either team. If 15 students are on the basketball team, 18 students are on the tennis team, 11 students are on both teams, and 14 students are not on either of these teams, how many students are in the class?

The students in a certain physical education class are on either the football team or the basketball team, are on both these teams, or are not on either team. If 12 students are on the football team, 15 students are on the basketball team, 8 students are on both teams, and 9 students are not on either of these teams, how many students are in the class?

Before personnel are lifted from a vessel in a personnel basket，the vessel should be（）.

If the survival craft is not loaded to full capacity，the personnel should be（）.

In order to improve the efficiency of the communication with shore personnel, you should（）

Personnel boarding a davit-launched liferaft from a ship should be checked to assure they are not in possession of or wearing（）.

ISM规则中，“公司”是指（）。 Ⅰ．船舶所有人； Ⅱ．船舶经营人； Ⅲ．光船租赁人。

（）, or drum is used for hauling in or letting out the wires or ropes which will fasten the ship to the shore.

Sometimes the contract（）that the lump sum freight must be paid in advance and will not be returnable even if the vessel and／or her cargo are lost.

If you do not know the subject, you will not understand what is said or written, even if English is your mother （） what is said or written.

ISM规则要求500总吨及以上的油船、化学品船、散货船建立并实施安全管理体系，对其它船舶目前没做要求。

If the towing bridle legs are not of equal length（）.