1.. The tourists __ by 9pm tomorrow. aren't returning won't return won't be returning won't have returned

The correct answer is "won't have returned."<br /><br />The sentence "The tourists won't have returned by 9pm tomorrow" indicates that the tourists will not have completed their return by 9pm the next day. This is a future perfect tense construction, which is used to describe an action that will be completed before a specific time in the future.