It was not until he arrived at the railway station（）he realized he had forgotten his ticket.

A. 一项新技术已经被研究出来，总产量在整体上已经提高了20%。
B. 一项新技术已经被研究出来，总产量提高了20%。
C. 由于研究出了一种新技术，总产量提高了20%。
D. 由于研究出了一种新技术，总产量在整体上已经提高了20%。

A. a pair of shoe
B. a piece of glove
C. ten slices of bread
D. a pieces of paper