问题
选择题
—Jack is not in the office at the moment
—Oh, he ______ those who are going to take the driving test in an hour.
A．can have instructed
B．must have instructed
C．must be instructing
D．will be instructing
答案
C
题目分析：考查情态动词。句意：杰克刚才不在办公室。他肯定正在指导那些一个小时内要驾照考试的学员。 根据上文提到Jack is not in the office at the moment 他刚才不在，故表肯定推测，推测刚才正在做某事must be doing,所以选C项。
考点 : 考查情态动词