11. The manager put forward a suggestion ____ we should have an assistant. There is too much work to do.
同位语从句用 that 引导，后接先行词所指代的具体内容。原题中 we should have an assistant 为 suggestion 的具体内容。故正确答案为B。
“ The manager put forward a suggestion ____ we should have an assistant. There is too much work to do.”经理提出了一个建议：我们需要一个助手。工作太多了。
语法结构不清致错。