两物体甲和乙在同一直线上运动,它们在0~0.4 s时间内的v-t图象如图1所示.若仅在两物体之间存在相互作用,则物体甲与乙的质量之比和图中时间t1分别为 ( )
How many ______ did you eat?A. biscuit B. biscuits C. a biscuit
Wang Fei ________ got a stomach ache.A. has B. have C. is
I ______ a new friend.A. has got B. got C. have got
Daming ___________ Grandma last Sunday.A. phoned B. phone C. phoneed
We went to _______.A. the great wall B. the Great Wall C. Great Wall