The girl downstairs practice __________ the piano every day.
A. play
B. playing
C. to play
D. played
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My father sent me _________ some milk for my grandfather.
A. buy
B. to buy
C. buying
D. bought
My classmates help me _________ my English.
A. learning
B. learnt
C. with
D. to be learn
下列是维生素B1主要来源的食物是 ( )
A. 蔬菜
B. 水果
C. 粮食
D. 牛奶
维生素B1在体内的辅酶形式是()
A. NAD+
B. TPP
C. FMN
D. FAD
E. 、CoA