It is five years ________ we saw each other last time.[ ]

Before a problem can be solved, it must be obvious ______the problem itself is.

Hi, Amy! How __________ your school trip to the beach—Hi, Tom! We __________ a good time there.

How nice the old Chinese book!—I bought it online last week. It ________ in ancient China.

They have arrived at lunchtime but their flight was delayed.[ ]