Vice President Kamala Harris will focus on defending international rules in the South China Sea, strengthening U.S. regional leadership during her trip to Vietnam and Singapore.

defend ﾃﾞｨ フェﾝﾄﾞ　v)守る･防衛する、擁護･支持する

strengthen スﾄﾚﾝｸﾞ ｾﾝ  v)強化する

I've been swimming to strengthen my upper body.

A set of exercises to strengthen the leg muscles.

The walls were strengthened with steel rods.     rod n)細長い棒

Japanese government's first priority is to strengthen the economy.

priority

 noun/praɪˈɒrəti/(plural priorities)

[countable] something that you think is more important than other things and should be dealt with first/優先事項