一、填空
1.He shaved his m________ off and looked younger than his age.
2.The new technique is targeted at mobile ________(仪器).
3.They sat down and d________ a letter to the local newspaper.
4.They e________ untold difficulties and dangers before they reached their destination.
5.He was one of the very greatest scientific and mathematical g________.
6.Father patted me g________ on my back, but said nothing.
7.I studied for my ________(博士学位) in Tsinghua University from 2013 to 2016.
