_____isthatbook?—It’s yellow.[ ]

Can you guess _________ the new Nike sports shoes?—Yes. Maybe he asked his grandpa to pay for them, I think.

She looks very sad. I want to help her, but I just don’t know ____ to do it.

Realizing ______ I had been able to accomplish, my fears of failure grew rapidly.

This orange sweater looks very nice. Can I _______?