Focus on the pronunciation of strengthen
English definition of “strengthen”
/ˈstreŋk·θən/, /ˈstreŋ-/ v [I/T] (BECOME POWERFUL)
› to become more powerful or more difficult to break, or to make something stronger: [T] If something isn’t done to strengthen the railroad bridge, it may collapse. [I] The tone of her voice strengthened suddenly. [T] Exercise will strengthen your legs.