The possible long-term health risks to airline personnel who repeatedly cross multiple time zones has been a concern since the first jet transports went into service in the 1950s.
The possible long-term health risks to airline personnel who repeatedly cross multiple time zones has been a concern since the first jet transports went into service in the 1950s.
A. who repeatedly cross multiple time zones has been a concern since the first jet transports went
B. who are repeatedly crossing multiple time zones has been a concern since the first jet transports that went
C. who repeatedly cross multiple time zones have been a concern since the first jet transports went
D. repeatedly crossing multiple time zones has been a concern since the first jet transports went
E. repeatedly crossing multiple time zones have been a concern since the first jet transports going
2.正确选项中: personnel who repeatedly cross 的cross用一般现在时是表达一般的规律吗?表达的是空乘经常穿越时区的一般规律?那为什么官方解释说B选项中“are repeatedly crossing” is the wrong tense, since it refers to airline personnel who worked as far back as sixty years ago.
然后解释中D,E选项中又没有说到时态的问题。是可以理解为personnel (who were) repeatedly crossing multiple...吗?如果是这样有没有错?