Sam finds sweeping robots useful，and he plans to buy _____for his grandma．（ ）
A．itB．oneC．thisD．that
﹣﹣﹣The weather report says we will expect a sunny day tomorrow．
﹣﹣﹣____． I am going to go climbing with my classmates．（ ）
A．Bad luckB．I hope so
C．Sounds terribleD．I'm afraid so
Not all children ____ watch this video will become a scientist， but some may become interested in science．（ ）
A．whomB．whichC．whoD．whose
﹣﹣﹣Have you decided ____ the Expo 2019 Beijing？
﹣﹣﹣This summer holiday．（ ）
A．how are you going to
B．how you are going to
C．when are you going to
D．when you are going to
Dirty air and water are harmful． They ____ kill plants， and even people．（ ）
A．canB．can'tC．shouldD．shouldn't
My father ____ in a panda protection center for 10 years， so he knows a lot about panda．（ ）
A．was workingB．is working
C．has workedD．will work