短语讲解：

1. All the paintings were created between 1850 and about 1970.

between ... and 在两者之间
例句：As are tensions between china and japan.
中日紧张关系也在加剧。

2. She says Duncan Philips bought the works at a time when European artists were more in demand. 

at a time 依次， 逐一， 每次
例句：Teach a word at a time.
一次教一个单词。

3. Duncan Phillips lent his support to many immigrant artists as well.

as well 也， 还有
例句：It was a missed opportunity as well.
它还是一个错失的良机。

4. He celebrated their approach to their American experience as being something that enriched us.

approach to 接近
例句：But here, it's infused with her compassionate approach to this man.
在这里，充满了她接近那个人的慈悲。