下列关于影响化学反应速率因素的说法不正确的是 [ ]

A. 催化剂能降低反应的活化能，提高活化分子百分数，加快反应速率

B. 改变温度能够改变活化分子百分数，改变有效碰撞的几率

C. 恒温恒压下增大压强（缩小体积）使单位体积内活化分子百分数升高，加快反应速率

D. 恒温恒容时充入气体反应物，提高单位体积内活化分子个数，加快反应速率

Her brother___ while he ___ his big horse and had his leg broken.

A．fell; was riding

B．fell; ride

C．had fallen; was riding

D．had fell; rode