用括号中所给词的适当形式填空。He felt very________(disappoint)because he missed the beginning of the concert.
When he was looking into a hole, a big cat appeared (突然地).
National Day is coming. I'm looking forward to (参观) Tian'anmen Square.
Sometimes we feel (孤独的) even though there are lots of people around.
This article tells us how to (避免) getting hurt while climbing.
He often (旅行)to beautiful places in the world.