worry about和be afraid of的区别

worry about和be afraid of的区别
RT 一个完形填空讲的是害羞
如How do you feel when you have to make a speech in front of class?What about when you go to birthday Do you get really shy?
Shyness means feeling nervous or frightened when you're around other people.Experts have found that more than 80 percent of middle school students feel afraid to be center of attention.Some kids are born shy.Some become shy later BECAUSE OF their life experiences.
It's OK if takes you a while to feel yourself again when you go to a new place or meet new people .In fact ,everbody gets a little shy sometimes .It's just a case of how much.
Most people have red faces and talk in BROKEN sentences when they get shy.But some become so shy that they won't go to a restaurant because they are too nervous to order and pay for their food.Some are afraid of meeting new people ,so they seldom go outside.This kind of shyness can be bad for a person.
If shyness doesn't stop you from doing something you want to do ,being shy isn't a very big problem .Some experts say shy people are clevers because they think more and talk less.Shy people are also good at working with others because they think more for other people .Some great people in history were shy,too.
You see ,being shy isn't all bad .But remember not to let good opportunities pass by just because of it If you have to sing a song at a birthday party or practice your spoken English in front of others ,juse do it There's nothing to be afraid of.
最后一个词组为何不能化成worry about（完形填空的答案）
还有第二自然段中的because of不能用for代替?
第三自然段中的broken为何不能用strange?
1喽for后面可以接短语我查了