My father keens on researching our family history.
我父亲喜欢研究我家的家族史。
2
No matter when you sit down in summer, you always roll up your pants to your keens.
在夏天，不管什么时候坐下，你都把裤脚卷到膝盖边。
3
The paper keens on missile azimuth aiming system, in particular, the measurement method of the precision on aiming system of the underwater to surface missile on the sea.