寄生虫病的流行特点有
A．有季节性，地区性和自然疫源性B．仅有季节性C．无地区性D．无季节性E．无自然疫源性
参考答案：A
—I've got a new job in New York.
—Oh, ______, but I'll miss you. [ ]
A. that's too bad
B. that's a problem
C. that's OK
D. that's great
柴油机调速器调速弹簧装配时预紧力（），弹簧内存在微观裂纹等，都会造成弹簧工作时断裂。
A.过小
B.过大
C.过大或过小
D.合适
