支气管哮喘急性发作时，控制症状首选的药物是（） ["po受体激动剂","糖皮质激素","抗胆碱能药物","茶碱类"]
接合生殖
义务论的具体表达形式是人们（）做什么和（）做什么，以及如何做才是道德的。
Which two design concerns must be addressed when designing a multicast implementation?（） [" only the low-order 23 bits of the MAC address are used to map IP addresses"," only the low-order 24 bits of the MAC address are used to map IP addresses"," only the high-order 23 bits of the MAC address are used to map IP addresses"," only the low-order 23 bits of the IP address are used to map MAC addresses"," the 0x01004f MAC address prefix is used for mapping IP addresses to MAC addresses"," the 0x01005e MAC address prefix is used for mapping IP addresses to MAC addresse"]
关于结核菌素试验结果的描述下列正确的（） ["结核菌素试验阴性可除外结核","结核菌素试验阳性，肯定有结核病","重症肺结核的结素反应均呈阳性","结核菌素试验阳性仅表示曾有结核感染"]
如何在教学中提高小学儿童的概括水平？
