专利权人有义务定期付给专利局管理费。（）
参考答案：对
Henry said he stayed at home all day, but I saw him in the supermarket. It’s __________that he was lying.
A．obvious
B．amazing
C．necessary
D．strange
The senator agreed that his support of the measure would jeopardize his chances for reelection.
A. benefit B. endanger C. hinder D. disturb
