22. The girl often helps her best friend, ______ is not good at English. To their delight, his English is improving day by day.
He observed a stranger _______ around the store at 12 p.m. last night.
Once ______ , the plan can’t be changed.
They asked me so many ______ questions that I got ______.
Jumping out of ______ airplane at ten thousand feet is quit ____ exciting experience.
Occasions are quite rare ______ I have the time to spend a day with my kids.