【正确答案】To give an example of frustration tolerance, the professor talks about his son building a tower with blocks.
According to the lecture, the boy tried to build a tower but failed and cried. The professor agreed to help, but always came a little later when his son asked him for assistance. The professor did this because he wanted his son to overcome difficulties and tolerate frustration on his own. In the end, the son could build a tower and also learned to solve his problem without crying and screaming first. So the boy built both towers and frustration tolerance.

【答案解析】[听力原文]
M: Like today's textbook reading said, ideally we are able to bear frustration better as we grow up. However, to tolerate frustration is never easy. We have to work hard on our own and sometimes even need others to help us.
Take my son as an example. When he was about three, he was busy one afternoon trying to build a tower with his building blocks. Only the tower fell down every time it got more than a few blocks high. And, since the boy was only three, he cried. He also asked me for help finally.
Well, I always say kids should learn to be independent, and helping him to finish the work is not beneficial for him. Kids need to learn to solve problems on their own. But, didn't want to listen to a sniveling little kid all afternoon. So I helped him build a tower, but a little later every time he asked. I was careful too, to explain why his towers kept falling down.
After that, every time he had trouble, I came to help a little later. Within a few weeks, my son could build his own towers. Plus he had learned not to ask for help and try to solve the problem on his own first, instead of crying or screaming when he had difficulty. So he was not only building towers, he was building frustration tolerance, too.

Alternative Wording(替换表达)
Synonyms (a)build—erect, construct
(b)to help—to come to one's aid
(c)overcome—vanquish
(d)cry and scream—throw a tantrum
Paraphrases 1. The professor was willing to lend aid, but gradually came later and later with each call for help.
2. Thus the boy learned both to build towers and to bear frustration.