Khan Academy sentence completion

One _______ of the Khan Academy is that it is free.

• advantage
• difficulty
• struggle
• amount

I tried to call you but you were not _________.

• available
• instruct
• process
• specialist

This is not my bag! Who does it ________ to?

• belong
• available
• private
• advantage

The test was vey _________ but I think I passed

• challenging
• difficulty
• instruct
• belong

__________ is important for artists and also for teachers.

• creativity
• pace
• provide
• widen

The goverment plans to _______ the train service.

• develop
• difficulty
• feedback
• private

It was dark when I got to my car, so I had _______ finding my keys.

• difficulty
• develop
• feedback
• instruct

In class we had a discussion in order to _________ opinions.

• exchange
• innovation
• pace
• solve

After a year at her job, her boss gave her ______ on how she was doing

• feedback
• struggle
• provide
• relative

I don't know how to do this, I need you to _____ me.

• instruct
• provide
• solve
• struggle