300
5. Most of the milk _____ gone bad. Six gallons of milk _______ still in the refrigerator.
a. has----are
b.have---is
has---are
-Most' is not a countable noun here (you can't count 'the milk' in the first sentence), so the verb must be singular. You can count the gallons of milk, though, so the subject in the second sentence is plural.