THE CORRECT ANSWER IS THEY'RE / THAN.DEFINITIONS

10. The correct answer is they're / than.Definitions: than is comparative; then is chronological or consequentialExplanation: See Definitions and Explanation in question 8 for usage of the words their and they're.In this sentence, we are comparing how smart they are and how smart you think they are, so we use the word than. Then is used when referring to time or consequences.Example: If you think there is going to be traffic, then leave sooner than you normally do."Then is referring to the consequences relating to traffic. Than is comparing leaving sooner and leaving when you normally do.