能够承受自船首方向的风、流推力和倒车的拉力,防止船位向后移动及外张的缆绳是()。
①头缆;②尾缆;③前倒缆;④尾倒缆;⑤横缆。
A.①④
B.②③
C.①③④
D.②③⑤
参考答案:A
As soon as I shut the front door, I realized that I ______ my key in the house. [ ]
A. had left
B. had forgotten
C. had put
D. had placed
用50mL 0.55mol/L NaOH溶液和50mL 0.25mol/L H2SO4溶液来做中和热测定的实验,测得溶液在反应前后的温度变化为t1℃~t2℃ (t2>t1),混合后溶液的比热容为c = 4.18J/(g·℃),溶液的密度都近似为1g/mL,中和热△H=_________(填表达式,不用化简) 若将H2SO4溶液换成相同物质的量浓度的CH3COOH溶液,测得的△H______填(“偏大”、“偏小”或“相同”)若将稀硫酸换成浓硫酸来做该实验,测得的△H________(填“偏大”、“偏小”或“相同”)