Birds fly in the sky. write this sentence in all other tenses.

I assume you mean the three tenses, but let me know if you need more.

Past Tense: "Birds flew in the sky."

Future Tense: "Birds will fly in the sky."

The sentence is already in the present tense.

many were disgusted, nauseated and shook their heads with disapproval upon finding out about the recycling of water process. however, they do not seem to understand that this process actually saves water.

although individuals may argue that it is unhealthy, and or unsafe to drink water that is "from toilet to tap" , the water is 100% safe to drink and involves forcing the water across a membrane, which "removes   any impurities, including viruses, pharmaceuticals and dissolved minerals" , according to paul rozin, a psychology professor who studies revulsion.

i agree that that the thought of drinking water that once ran through someones kitchen sink isn't quite appealing, but recycled wastewater is safe to drink. it also saves water. "the city produces nine million gallons a day" claims russell schreiber, the city’s director of public works.

recycled waste water has absolutely no health concerns whatsoever. when wastewater goes into a system, it's absorbed back into the ground. thus, it goes into a sewer system, then goes through a treatment process that removes contaminants before being released. nonetheless, there is no problem in drinking water that has been recycled.

"in drought-ed california, there are six state agencies that use wastewater that comes from an intellectual property source," according to the university of california, riverside. studies show that this water is completely safe to drink, however, it still doesn't mean people are going to happily pour it in a water glass.

researchers hope it "may make consumers more amenable to drinking recycled wastewater," extraordinarily, women who have a higher "disgust reaction" and make most consumer purchasing decisions.

the answer is d: message a character's thoughts