第17题:[多选题] 下面属于5G NR上行链路reference signal的是 A.Demodulation reference signal for PUSCH B.Phase-tracking reference signals for PUSCH C.Demodulation reference signal for PUCCH D.Sounding reference signal 参考答案:ABCD
第27题: [单项选择]--I’d like to invite you to a concert this evening. --Thank you, but ______ I’ll be free I’m not sure at that moment. [A] while [B] if [C] when [D] whether 参考答案:D 答案解析:[精解] 本句的正常语序为but I’m not sure whether I’ll be free at that moment.意为“我不能确定到时是否有空。”whether和if都能引导宾语从句