（）is a computer technology that headsets,sometimes in combination with physical spaces or multi-projected environments,to generate realisitic images,sounds and other sensations that simulate a user’s physical presence in a virtual or imaginary environment.

设a=′′a′′，b=′′b′′，c=′′c′′，d=′′d′′，执行语句x=IIf（（ad），′′A′′，′′B′′）后，x的值为（　　）。

大学英语（一）（二）（三）（四）课程考核和全国高等学校英语应用能力考试（A级）成绩以百分制记载，（）分为合格。全国大学生英语等级考试以710分制记载，（）分为合格。

What must the Master or person in charge of a ship enter in the logbook after conducting a boat drill? （）

60.  A from time to time   B  in time    C  sooner or later   D on occasion

The purpose of the skirt or trunk in four-stroke cycle engines is to act in a similar manner to a （）.

EXCEPT when suffering from a head or chest injury a patient in shock should be placed in which position?（）.

 ______ twice a year, whether it is a car or a bus or a truck, is the rule that every driver must obey in this city.

64. A in this case    B in any case    C in no case    D in some cases

In the case of an injury causing a person to be incapacitated，the Master or person in charge of a mobile offshore drilling unit must submit a report to the（）.

SOLAS requires a lifesaving training manual be provided in each crew cabin or in the（）.

已知“A、B二人中至少有一人懂英语”、“只有B刁懂英语，A才懂英语”和“A不懂英语并且B也不懂英语”这三个判断中，只有一个为真。据此，便可必然推出下列判断中为真的是（）。