it's dangerous (driving) a car at such a higt speed.为什么用ing?

it's dangerous (driving) a car at such a higt speed.为什么用ing? is dangerous _a car at such a high speed. 1.It is dangerous _______a car at such a high speed.C She rode a car at_____I think is a dangerous speed. a car travelled at a speed of 90km/h.it left town ponpon at It's reported that this high-speed （ ）at speed of 417 km/h A It's _____ to me.A.dangerous B.danger 为什么? the old man drove the car at a speed,maki The car was going at a s_______ speed. It's a car ( ). How t___________ it is to do such a dangerous thing! at speed 还是at a speed