A _______ number of mothers with young children are stopped from undertaking paid work because they lack access to childcare.

A．considerate

B．critical

C．fundamental

D．substantial

子曰：“人而无信，不知其可也。大车无，小车无，其何以行之哉？”这句话的主题是（）。

A.友谊

B.勤奋

C.诚信

D.守时