关于甲型肝炎,下列哪种说法是不正确的()
A.未发现慢性带菌者
B.潜伏期末已有传染性
C.呈周期性
D.无季节性
E.感染后可以获得持久免疫力
参考答案:D
________ to an Australian home, you will probably eat outside and cook meat on the open fire.
A.Asking
B.Being asked
C.If asked
D.If asking
上午无云,日照纸记录完好,下午无云,但无日照记录,该天日照时数如何计算?