问题
计算题
某非金属元素R的氧化物中含有R 40 %，R元素的化合价为 +6价，该元素的原子核内质子数等于中子数，试通过计算，推测元素R的氧化物的化学式。
答案
SO3
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某非金属元素R的氧化物中含有R 40 %，R元素的化合价为 +6价，该元素的原子核内质子数等于中子数，试通过计算，推测元素R的氧化物的化学式。
SO3
| 用所给单词和短语的适当形式完成下列句子。 | |
2. No one has come up with a ____ explanation of why dinosaurs died out. 3. ____ is famous for its milk and cheese. 4. Because of the earthquake, all the supplies of electricity and water have ____. 5. The car rushed at the bridge at ____ speed. 6. I feel very ____ and lonely. 7. The best ____ goes to them. 8. Driving with ____ tread(s) (轮胎) can be dangerous. 9. How could you ____ your own motorbike in a sea of motorbikes? 10. We are now living in a very bad condition but someone is even ____. |