There _____ two cups of tea on the table.A、isB、areC、was
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——“Who are you going to play ()? ”—— “Grade two”.A、aboutB、withC、against
A.about
B.with
C.against
The students put down their pens when the teacher _______ them to stop writing.A、bega
A.began
B.told
C.walked
蔬菜中含有丰富的营养素,特别是富含维生素和()。
A. 营养素
B. 矿物质
C. 叶绿素
D. 蛋白质
传热实验时,在套管换热器中用饱和水蒸气冷凝来加热空气(空气走内管,蒸汽走环隙),为强化传热决定加装翅片,翅片应装在()侧更为有效。
A. 外管外
B. 外管内
C. 内管外
D. 内管内