strengthen
v.
late 14c., from strength + -en(1). Related: Strengthened; strengthening; strengthener. Earlier verb was simply strength (12c.).
〔李〕[strength n. 力量；-en ⇒“to cause to have strength使有力量”→] v. make strong使坚强，加强
〔李〕[strength n. 力量；-en ⇒“to cause to have strength使有力量”→] v. make strong使坚强，加强