In fact, ＿＿＿is a hard job for the police to keep order in an important football match.

A．this

B．that

C．there

D．it

诊断接触性皮炎最常做的皮肤试验是（）

A.皮肤划痕试验

B.皮肤斑贴试验

C.皮内试验

D.被动转移试验

E.食物排除试验