Tom was very anxious for the coming exam and told me worriedly, “______, I suppose I'm frightened of

题干

Tom was very anxious for the coming exam and told me worriedly, “______, I suppose I'm frightened of failing.”

A：On the way

B：In a way

C：In the way

D：By the way

上一题下一题 0.0难度选择题更新时间:2017-11-17 10:22:05

B

实验原理：固体培养基中难溶性磷酸盐在微生物作用下溶解，会在菌落周围形成透明圈，透明圈直径（D）与菌落直径（d）的比值（D/d）代表微生物溶解磷的能力大小．

实验步骤：步骤1 取某地区土样5g制得土壤溶液后稀释，取稀释液1mL接种到基础培养基A上，在适宜温度下培养72h．步骤2在基础培养基A上用接种环挑取代表性菌落再次接种，培养3～4d后观察菌落特征和透明圈的大小，初步筛选出三种优良解磷菌株（如表）．

请分析回答下列问题：

温度/℃	0	10	20	30	40	50	60	70	80
溶解度/g	29.4	33.3	37.2	41.4	45.8	50.4	55.2	60.2	65.6