一、单项填空(每小题1分,满分15分)
从每题所给的A、B、C和D四个选项中,选出可以填入空白处的最佳选项。
1. What ______ useful information they gave us!
A. a B. an C. the D. /
2. Qianweichang, a famous scientist, the expert of mechanic and maths passed away ______ the morning of July 30, 2010, but we will remember him forever.
A. at B. on C. by D. in