802.11a的采用()调制技术以提高信道利用率。
当气温低于几度时,灰土不宜施工?
不受季节影响,随时可采的药材有() ["A、矿物类药材","B、动物化石类药材","C、结石类药材","D、两栖动物类药材","E、真菌类药材"]
办理汇出汇款业务时,私人VIP客户可以免去的汇款费用是()。 ["A、汇款手续费","B、汇款电报费","C、CHARGE OUR费用","D、本金保证汇款费用"]
在试验室搅拌砂浆时应采用机械搅拌,搅拌时间不少于() ["60S","120S","150S","180S"]
绝骨