oil rigs have to be repaired frequently and divers,who often have to work in darkness a hundred feet

题目

oil rigs have to be repaired frequently and divers,who often have to work in darkness a hundred feet under water,have been frightened out of their wits by giant fish bumping into them as they work.这里的bumping into为什么要用ing形式呢?而且have been frightened out of their wits这里为什么要用现在完成时态呢

答案

bumping into them as they work 做fish的ing形式的定语.
divers ..have been frightened out of...潜水员们被那些巨型大鱼吓的六神无主.是过去发生的事情,且对现在的观点陈述有影响,所以用 现在完成时态.