strengthen
英 ['streŋθ(ə)n; -ŋkθ(ə)n]
美['strɛŋθn]
	    - vt. 加强;巩固
 - vi. 变强;变坚挺
 
英英释意
- 1. make strong or stronger;
 - "This exercise will strengthen your upper body"
 - "strenghten the relations between the two countries"
 
- 2. gain strength;
 - "His body strengthened"
 
- 3. give a healthy elasticity to;
 - "Let's tone our muscles"