It was not until the 18th century that man realized that the whole of the brain was involved in the working of the mind，　　　　？

A．was it

B．wasn’t it

C．did they

D．didn’t they

沈阳恒昌机电公司计划从德国进口一批液压电动机(属自动进口许可管理的机电产品)，在与外商签订合同之前，外商寄来一批样品作为货样，价值5 500美元，按照我国现行对机电产品的管理规定，该批机电产品可以不申领“自动进口许可证”。( )