大家帮忙看下这句的大致意思? the solution is cooled in an efficient freezing mixture to 5°, and a cold solution of 107 g. (1.47 moles) of 95 per cent sodium nitrite in 150 cc. of water is added dropwise with vigorous stirring at such a rate that the temperature remains between 5° and 7°. with efficient cooling about one-half hour is required to add the nitrite. the mixture is stirred for one-half hour longer and then allowed to stand for four hours, during which time it warms up to room temperature. 最后一句的during which time it warms up to room temperature指的是4个小时的室温而不包括前半句的一个半小时吧 查看更多