1 . Doctor Yuan , _______ (know) as the father of hybrid rice, passed away on May 22, 2021 (所给词的适当形式填空)

2 . She takes pride in_________(know) eight languages. （所给词的适当形式填空）

3 . When I ran into him in the supermarket, he pretended not _________（know）me. （所给词的适当形式填空）

4 . The poor child stood there, not_________(know) what to do, and turned to his father for help. (所给词的适当形式填空)

5 . _________ which university to attend, the girl asked her teacher for advice. (Not knowing, Knowing not) (用正确动词形式填空)

6 . _________（know）the new version is not available, I have to download the original version of the software. (所给词的适当形式填空)

7 . ____________（know）the difference between the two research findings will be helpful to your experiment. (所给词的适当形式填空)

8 . He let out my secret. He made it ________ (know) to all. （所给词的适当形式填空）

9 . She is one of the teachers who ________(know)Japanese in our school. （所给词的适当形式填空）

10 . Neither his parents nor he_________(know) anything about it now. (所给词的适当形式填空)