布氏姜片吸虫成虫的形态特征之一是()

A．二睾丸呈分支状

B．二睾丸呈珊瑚状分支

C．睾丸分4～6支，长条形

D．睾丸7个，呈串珠状

E．睾丸在虫体前半部作左右排列

Mrs.Smith finds it hard to clear up the mess，as her children are always ________ whenever she tries to.                                                     (2013·福建，29)

A．in the way

B．on watch

C．in sight

D．on the line