I cannot <em><u>believe</u></em> that she would be selfish enough to do something like that!
My <u><em>science</em></u> class went on a trip to the zoo.
Explanation:
"I before E, except after C" is a rule of thumb that many children learn when they are beginning to write in English. The rhyme tells us that, when unsure between using "ie" or "ei" in a word, you should look at the preceding letter. If the previous letter is a "c," then the sequence is most likely "ie." However, this rule has some exceptions, as shown by words like "science."