Jack could have avoided that terrible car accident, but he careful enough.
A. is not
B. was not
C. hasn’t been
D. hadn’t been
网友回答
A. is not
(答案→)B. was not
C. hasn’t been
D. hadn’t been
解析：考查时态。根据could have avoided可知本句是对过去所发生情况的虚拟，but后面使用陈述语气，所以使用过去时。句意：Jack本可以避免那可怕的事故，但是他不够小心。