Where had he worked before 1990?
1990年之前他在哪里工作？
Had he worked harder, he would have gotten though the exams.
如果他努力了的话，他就会通过考试的。
Had he worked there before 1990?
1990年之前他在那里工作吗？
Had he worked here for 10 years before I came?
在我来以前，他已经在这里工作10年了吗？
Had he worked harder, he would have got through the exams.
他当时要是学习努力点的话，就会通过这些考试了。
Had he worked harder, he would have got through the exams.
他当时要是学习努力点的话，就会通过这些考试了。
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