can; may; able to; to approve; to permit; certain(ly); to suit; (particle used for emphasis)[cedict]
熟練
shú liànㄕㄨˊ ㄌㄧㄢˋ
practiced; proficient; skilled; skillful[cedict]
掌握
zhǎng wòㄓㄤˇ ㄨㄛˋ
to grasp (often fig.); to master; to know well; to understand sth well and know how to use it; fluency; to control; to seize (initiative, opportunity, destiny)[cedict]