病人因就诊或住院所花费的交通费为
A．RCTB．模型分析C．人群研究D．回顾性研究E．WYP
参考答案：E
(2009·北京)At first he hated the new job but decided to give himself a few months to see ________ it got any better.
A．when
B．how
C．why
D．if
中毒性疾病的特点多为突然发生，具群发性，但无传染性。（）
