干眼病（）
A.维生素B1缺乏
B.核黄素缺乏
C.维生素A缺乏
D.维生素C缺乏
E.烟酸缺乏
参考答案：C
土壤有机质按其组成可以分为（）
A、非腐殖物质
B、腐殖物质
C、胡敏酸
D、富里酸
Which of the following statements is true according to the speaker
A．It will be in orbit on March 15.
B．Fleas are infesting the pets.
C．Yours is a position of great honour.
D．March 15 is the last day to submit a petition.
