Lieberman-Burchard反应的试剂是()
A.α-萘酚和浓硫酸
B.三氯化铁和浓硫酸
C.醋酐和浓硫酸
D.三氯乙酸和浓硫酸
E.苯胺和浓硫酸
参考答案:C
They arrived at a farmhouse, ______. [ ]
A. in front sat a small boy.
B. in front of it sat a small boy.
C. in front of which a small boy sat.
D. sitting in front of which was a small boy.
一般来说,服务的“()”构成部分在服务中占比例越大,构成服务人员的因素就越重要。