With all due respect 恕我直言,我冒昧地说一句
I understand what you're saying,but with all due respect I've been studying this topic for a lot longer than you have.
我明白你说的.可是恕我直言,我学这个比你时间长多了.
With all due respect,you're just not ready to take responsibility for the entire project.
我冒昧地说一句,你现在还没能力负责整个项目.