For a hydrogen-like atom, the energy [img=119x51]1803bd5d31efe8a.png[/img]. The electronic energy of [img=32x21]1803bd5d3a864a7.png[/img]in the [img=18x18]1803bd5d426aa1b.png[/img] state is A: one-ninth that of H in the 1s state. B: nine times that of H in the 1s state. C: four-ninths that of H in the 1s state. D: nine-fourths that of H in the 1s state.

____ of the land ____ covered with water. A: Three fourth; is B: Three fourth; are C: Three fourths; is D: Three fourths; are

________ of the earth ________ covered by sea. A: Three fourth; is B: Three fourths; is C: Three fourth; are D: Three fourths; are

There are _____ students in their school. A: nine hundred B: nine hundreds C: nine hundred of D: nine hundreds of

11.She went to the countryside ______.　　a. in the morning at nine on June first,1968 b. on June first,1968 in the morning at nine　　c. at nine in the morning on June first,1968 d. on June first,1968 at nine in the morning A: in the morning at nine on June first,1968 B: on June first,1968 in the morning at nine C: at nine in the morning on June first,1968 D: on June first,1968 at nine in the morning

Three fourths of the surface of the earth__________with water. A: is covered B: are covered

—How old is your daughter? — () . We had a special party for her () birthday last week. A: Ninth; ninth B: Nine; nine C: Ninth; nine D: Nine; ninth

- How old is your son? - _____. We had a special party for his _____ birthday last Sunday. A: Nine; nine B: Nine; ninth C: Ninth; ninth D: Ninth; nine

There are ___________ students in the school. A: nine hundred of B: nine hundreds C: hundreds of

The Black Death ravaged England, carrying off three fourths of the population.