NO的合成底物是（）
A.精氨酸
B.单甲基精氨酸
C.胍氨酸
D.氨基酸
E.核糖核酸
参考答案：A
麻疹早期诊断最有意义的I临床表现是
A．有感冒病史
B．耳后淋巴结肿大
C．Koplik斑
D．发热、流涕、咳嗽
E．手、足出现红色斑丘疹
I was scared and feeling pretty anxious, _______in a new country.
A．for the first time I was
B．I was the first time
C．being the first time
D．this being my first time
