Answer:
Several <u><em>building</em></u> surrounding the Willis     (should be buildings)
Tower have equally attractive interiors. They
offer beautiful views of the city <u><em>to.</em></u> However,     (should be too)
the Willis Tower is the best choice for any
company. <u><em>Weather</em></u> the idea of a view is     (should be Whether)
appealing or not, <u><em>customer's</em></u> will be       (should be customers)
impressed by the <u><em>buildings</em></u> size.     (should be  building's)
DONE
Explanation:
Add -'s <em>apostrophe s </em>to make a noun possessive.  Normally, plural nouns are by adding s.  No apostrophe!  Some nouns have irregular plural forms, like man > men,  child> children, woman> women,  ox> oxen, deer> deer.