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.