钻石在宝石中最贵重，与它有“姊妹”宝石之称的是_____和_____。

A. The work of the two Nobel laureates sheds light on the tiny building blocks of life-cells.
B. The work of the three Nobel laureates sheds light on the huge building blocks of life-cells.
C. The work of the three Nobel laureates sheds light on the tiny building blocks of life-cells.
D. The work of the three doctors sheds light on the tiny building blocks of life-cells.

At
B. After
C. Not until
D. Before

A. talked
B. being talked
C. talked to
D. being talked to