(A) Sometimes two words look the same, but have different meanings and are pronounced differently (homographs).
Example: TEAR

1. VERB – tear-tore-torn: to cause a split or break in paper, clothes, etc. It rhymes with BEAR, PEAR, WEAR.
2. NOUN – a droplet of water coming from the eyes when crying. It rhymes with DEAR, FEAR, GEAR, HEAR, NEAR, YEAR.

(B) Some words of two syllables can change from a verb to a noun by shifting (moving) their word stress, though the written form remains identical.
Example: PROGRESS

1. “We want to progress as quickly as we can. There’s a lot of work to get through.” 
2. “You’re making slow progress. You need to make a bit more of an effort.”

1. VERB – to advance, to improve: PRO’GRESS – the stress falls on the second syllable.
2. NOUN – a general improvement, taking steps in the right direction: ‘PROGRESS – the stress falls on the first syllable.

Note that the mark [ ‘ ] goes before the stressed syllable. 

Exercises – Interactive Material

1. WORD STRESS  Words in context. Interactive, links to news stories, audio clips. Hot Potatoes format.
2. STRESS MONSTERS  Space Invaders Game. Identify the stressed syllable. New Headway Advanced, OUP.