Our teachers were very happy because ______ failed the exam.
A:somebody
B:anybody
C:nobody
微生物的种类繁多。艾滋病是由下列哪种微生物引起的( )
巴尔扎克说:“挫折和不幸,是天才的进身之阶;信徒的洗礼之水;能人的无价之宝;弱者的无底深渊。”这说明( )