Mr.Jones, _______ a great loss last year, has no courage to go on with his business. [ ]

A. suffering

B. to suffer

C. suffered

D. having suffered

汽车前轮前束的主要作用是（）汽车前进中因车轮外倾和纵向阻力使车轮前端向外滚动所造成的滑移。