Mrs Smith finds it hard to clear up the mess, as her children are always______ whenever she tries to.

A．in the way

B．on watch

C．in sight

D．on the line

衡量一家企业经营实力和经营成果的主要标志是( )。

A．投资规模

B．市场份额

C．销售额

D．投资报酬率