以下情况中，（）不是失效专利。
A、超过专利法定保护期限
B、专利权人以书面声明放弃其专利权
C、未按规定交纳年费
D、专利权人转让其专利权
参考答案：D
用方框中单词的适当形式填空。
1.I_________time with my best friend last Sunday.
2.The monitor often _________after-class activities.
3. There will be_________ pollution and fewer cars in the future.
4. Yang Liwei is an astronaut, and he is one of the most famous national_________ .
5.I don't think he _________with you if you do such a silly thing.
商品的防霉腐方法主要有（）。
A.气相防霉腐
B.干燥防霉腐
C.辐射防霉腐
D.化学防霉腐
