《扩大国家免疫规划实施方案》中要求严格实施疫苗的冷链运转,做好扩大国家免疫规划疫苗的()各个环节的冷链监测和管理工作。
A、采购
B、储存
C、运输
D、使用
参考答案:B, C, D
—______ he happy to see his mother?
—Yes, he ______. [ ]
A. Does; does
B. Is; is
C. Does; is
D. Is; does
Reliable delivery of messages is ensured by()techniques.
A.forward error correction
B.aftward error correction
C.DGPS
D.error-free and low error reception