Word Stress in English
Most English words involve only a binary stress distinction: syllables are either strong or weak. We are careful to make this distinction in all words because in some words it is the sole difference in pronunciation between words having different meanings: PERfect (adjective) / perFECT (verb), INcrease (noun) / inCREASE (verb).
This on/off stress distinction is what poets organize to create most English verse. Understanding verse structure requires one to be conscious of stress distinctions that are purely automatic and subliminal in ordinary circumstances. You can gain or improve your conscious awareness of this aspect of language by doing exercises.
To discover where primary stress goes in the words in this exercise, speak each word aloud and place special emphasis on the syllable that you think should be stressed. If the result sounds like Martian, you made a mistake. If it sounds like English, you were right. Identify the syllable bearing primary stress in each of the following words.