血吸虫病急性感染与季节有很大关系，常发生在（）
A.1～4月
B.4～9月
C.9～12月
D.1～12月均有发生
E.没有季节性
参考答案：B
It has been announced that students shall remain in their seats until all the papers _____.[ ]
A. will be collected
B. were collected
C. have been collected
D. have collected
保证的法律关系的参加方应当至少包括( )。
A．保证人
B．债权人
C．第三人
D．被保证人(债务人)
E．公证人
