预报辐射雾主要判断未来最低气温是否（）露点，如最低气温（）露点，则预报有辐射雾出现。
参考答案：低于；低于
My brother_________ Beijing many times. He __________ Nanjing for a week.
A．has been to, has gone to
B．has been to, has been in
C．has gone to , has been in
D．has gone to, has been in
缓解心绞痛的硝酸甘油最好的给药途径是：（）
A、口服
B、舌下含服
C、肌内注射
D、静脉注射
