下列关于地下工程管线敷设的说法，何项不妥？（　　）

A.常由β-溶血性链球菌感染所致
B.感染严重程度与病变轻重一致
C.可通过循环免疫复合物而致病
D.可通过原位免疫复合物形成而致病

A．SELECT * FROM student WHERE YEAR(birthday) NOT IN(1997, 1999);
B．SELECT * FROM student WHERE YEAR(birthday) IN(1997, 1999);
C．SELECT * FROM student WHERE YEAR(birthday)=1997 AND YEAR(birthday)=1999;
D．SELECT * FROM student WHERE YEAR(birthday) EXISTS(1997, 1

A.纤维蛋白原减少
B.脾功能亢进破坏血小板增多
C.凝血酶原减少
D.凝血因子X减少
E.凝血因子Ⅶ合成减少