（7）ling/o：
（7）ling/o：
7 O' clock表示时间 ______
7 O' clock表示时间 ______
The plane ______ off at 7 o’clock.
The plane ______ off at 7 o’clock.
They are____(leave) only at 7 o’clock.
They are____(leave) only at 7 o’clock.
Time of the party: on 50______ at 7 o’clock in the evening.
Time of the party: on 50______ at 7 o’clock in the evening.
He ____(get) up at 7 o’clock in the morning.
He ____(get) up at 7 o’clock in the morning.
用K2Cr2O7标定Na2S2O3溶液浓度｛c（Na2S2O3）=｝计算公式为（ ）。 A: mK<sub>2</sub>Cr<sub>2</sub>O<sub>7</sub>/M(1/6K<sub>2</sub>Cr<sub>2</sub>O<sub>7</sub>)×V B: mK<sub>2</sub>Cr<sub>2</sub>O<sub>7</sub>/M(K<sub>2</sub>Cr<sub>2</sub>O<sub>7</sub>)×V C: mK<sub>2</sub>Cr<sub>2</sub>O<sub>7</sub>/M(1/2K<sub>2</sub>Cr<sub>2</sub>O<sub>7</sub>)×V D: mK<sub>2</sub>Cr<sub>2</sub>O<sub>7</sub>/M(1/3K<sub>2</sub>Cr<sub>2</sub>O<sub>7</sub>)×V
用K2Cr2O7标定Na2S2O3溶液浓度｛c（Na2S2O3）=｝计算公式为（ ）。 A: mK<sub>2</sub>Cr<sub>2</sub>O<sub>7</sub>/M(1/6K<sub>2</sub>Cr<sub>2</sub>O<sub>7</sub>)×V B: mK<sub>2</sub>Cr<sub>2</sub>O<sub>7</sub>/M(K<sub>2</sub>Cr<sub>2</sub>O<sub>7</sub>)×V C: mK<sub>2</sub>Cr<sub>2</sub>O<sub>7</sub>/M(1/2K<sub>2</sub>Cr<sub>2</sub>O<sub>7</sub>)×V D: mK<sub>2</sub>Cr<sub>2</sub>O<sub>7</sub>/M(1/3K<sub>2</sub>Cr<sub>2</sub>O<sub>7</sub>)×V
Lily gets up at 6 o'clock in the morning. Lisa gets up at 7 o'clock in the morning.
Lily gets up at 6 o'clock in the morning. Lisa gets up at 7 o'clock in the morning.
已知P(A)=O,7，P(A-B)=0.4，求P(AB)=
已知P(A)=O,7，P(A-B)=0.4，求P(AB)=
I go to school( ) 7 o’clock in the morning. A: at B: in C: on D: for
I go to school( ) 7 o’clock in the morning. A: at B: in C: on D: for