D )7.My parents always ask my sister and me to be back 10 p.m.on weekend nights. A.until B.in C.on D.by C )8.I believe that all problems can_,no matter how difficult they are. A.solve B.solving C.be solved D.to solve 导航页导航页 ( )7. My parents always ask my sister and me to be back 10 p.m.on weekend nights. A. until B. in C. on D. by ( )8. I believe that all problems can , no matter how difficult they are. A. solve B. solving C. be solved D. to solve D C