Fill in the blanks with an appropriate word from the given options:

The group ______________ ideas for the presentation when their leader encouraged them to think ______________ for a creative solution.

In the sentence, we're using the past continuous tense ("was brainstorming") because it describes an action happening in the past when something else occurred. The group was in the middle of brainstorming ideas when their leader gave them a suggestion. The past continuously helps us focus on the action already in progress.

The phrase "think outside the box " means to think creatively or look at things from a new perspective. When leaders say this, they encourage the group to move beyond conventional ideas and develop something unique or innovative. It's a common phrase used in brainstorming or problem-solving contexts.