VOA慢速英语:How a Family Helped Save American Folk Music

not only but是not only,but also的变体。

As well是副词短语，其义为“也”，相当于too，它一般放在句末，有时和连词and或but搭配使用。例：

He is a worker，and a poet as well．
他是工人，但也是诗人。

China possesses enormous quantities of coal and is rich in other minerals as well．
中国拥有大量煤炭，其他的矿藏也很丰富。

Mr．Liu can speak English，but he can speak Cantonese as well．
刘先生会说英语，但他也能讲广东话。

2.In exchange, he agreed to travel throughout the United States to make recordings that would become the property of the archive at the library.

in exchange for为了换取,作为对…的交换

例句：Wool from Britain may have been traded in exchange for wine.
      过去英国的羊毛可用来换酒。

而in exchange则一般用作状语。

3.And they were part of this very exciting groundbreaking work in the nineteen tens, twenties, thirties, into the forties and beyond, of showing the United States what it was, what it had in terms of grassroots cultural heritage.

in terms of根据,按照,用...的话,在...方面

例句：In terms of leather shoes and fashion, Italians are ahead of the field.
      意大利人走在皮鞋业和时尚领域的前沿。

4.so that some of the whites wouldn't single him out and beat him up or whatever.

single out挑出,挑选出

例句：Jerry was singled out as the best student.
       吉利被选为最优秀的学生。