This one I see quite commonly: the present tense of the verb to lead is “lead”. The past tense is “led”:

• “Our work lead to several results.” WRONG
• “Our work led to several results.” RIGHT

Why is this so confusing? It is probably due to the similarity of “to lead” to the verb to read:  namely, both the present tenses and the past tenses of the two verbos rhyme when spoken aloud. However, while the present tense “read” and “lead” are spoken (with a long “ee” vowel) and spelled similarly, the past tense “read” and “led” sound alike (with a short “eh” vowel) but are spelled differently.

This, I am sad to say, is one of the many examples of the very complex relationship between the way English words are spelled and spoken. However, the good news is that this behavior, at least for verbs, is limited to irregular verbs like “read” and “lead.”