食品添加剂
防腐剂
就中国而言，过去2000年间，有哪些时期平均气温明显偏低？（） ["魏晋南北朝","唐代","宋代","清代"]
除（）色外，大多数合成尖晶石具有特征的吸收光谱。 ["红","蓝绿色","蓝","绿"]
What will the H.323 gateways do when they receive a call request?（） ["forward an admission request to the local gatekeeper","forward an admission request to the remote gatekeeper","send a location request to the remote gateway","send a location request to the remote gatekeeper"]
种植园
