下列哪种说法符合猩红热（）。
A.它是由棒杆菌属的种引起的
B.它是一种病毒性疾病
C.它是真菌疾病
D.它是由化脓链球菌引起的
参考答案：B
We ________ here on time but we were caught in a traffic jam.
A．must have arrived
B．could have arrived
C．need have arrived
D．should have arrived
利率期货的标的物是利率指数。
