氯化钾中氯离子对种子发芽和幼苗生长有()作用,故不宜作种肥。
A、促进
B、中和
C、缓冲
D、抑制
参考答案:D
—Why do you look sad?
—There are so many problems ________.
A.remaining to settle
B.remained settling
C.remaining to be settled
D.remained to be settled
VPN是利用公共网络基础设施,通过_________技术等手段达到类似私有专网数据安全传输的一种技术。