Read the beginning of the story below and complete the story in 600-800 words.
An Unexpected Guest
Riya was terrified when she heard the news on television that an alien spaceship had landed in her city. As a precaution, her father closed all the doors and windows.
Though everyone was asleep, Riya could not sleep a wink. The thought of aliens in her city kept her mind racing. It was almost midnight when she heard the door bell ring.
By now she was really scared. She ran towards the door but her father instructed her to go back to bed. She pretended to go towards her room, but hid behind the sofa and watched her father open the door.
由于基本未练习过记叙文写作，最开始看到题目时，我有些手足无措。但看到题目"An unexpected guest”和故事开头后，我确定了这是一篇科幻性文章的续写，对创造性写作的要求比较高，故而比较放心地大胆想象。
As her father opened the door, suddenly, a beam of brilliant light glimmered and scattered into the whole room,blazing like dancing fire.
"Wow!" exclaimed Riya with widely opening eyes.
A tremendous object totally blocked the door. It had a humanlike skeleton, with a round head, strong arms and legs,a waist as thick as a cow. On its face, two lighting blue dots standed for the eyes, and an outstanding steel line turnded down into a curve-- though it's hard to read its countenance, it's easy to feel its melancholy by his air. Besides, his fat face is covered with grey dusts, as if he came from the dustbin on the earth, not the sky.
"Go back to your room!" her father looked back and shouted, "Hey guy, what are you doing here?" He turned back to the strange object, with subtle trebling in his voice.
"Hey man," he said politely, put his left hand in front of its chest and gave a deeply bow. "I'm the ambassador of the Greenish Place, a very beautiful planet just like the Earth twenty million years ago. But these days, some nasty substances invaded our home, and we discoverd that them came from your planet..." Riya listened carefully, and creeped towards the door unconciously.
"So what?" her father shouted unpatiently, attempting to close the door.
"Wait,"the object put his right hand on the door, " I noticed your backyard is like a derelict dump, so I'd like to beg you..."
"That can't be true!" Riya's father cried in outrage and put the object out of the door.
"If so, I have no choice but take the girl to see it," the object drew a soft, long breath, and take Riya under its arms, rocketing into the sky, finally vanished into the distance.
"Riya--"her dad's scary and long shout left far away behind them.
While floating in the sky, the object hugged the shiveing girl totally lost in words,opened its mouth again:"Dear girl, don't be panic and I won't hurt you. I just want to show you to see your city's terrible environmental condition."
"What's terrible?" asked Riya in a low voice. A curious beast slowly stretchend and purred within her bosom, gradually overcoming her fear.
"Look here." the object blowing away the heavy smog lasting for days, pointed at the ground.
In the local industry site, the black smoke were flying into the night sky,drifting like a lone black snake, veiling all the shining stars with a strifling cloth. Enormous working trucks howling in the night, breaking all the peace away. Riya gazed in silent, with memories flowing back. Ten year ago, this had been a local garden, filled with children's laughters instead of smoke.
Next to the industrial working cite, lied a black velvet. After gazing at it closedly, Riya surprisedly found that it was a river! Years ago, she had alway put her bare feet into it, catching little fishes in the clear water.
Located beside the river, a derelict dump. Next to it, a smoking indurstry again...
"See, that is your planet, a melancholy place..." the object sigh with gloom
"Oh no! That cannot be true!" Riya closed her eyes, letting out a desperate loud shout trembling the peacefully shining star.
"Your human beings should pay for it!" after the final shout of the object, it loosed the arms, letting Riya falling into the sky.
"Oh no!" exclaimed her. She suddenly opened her eyes, found herself lying on her bed. It was a nightmare.
Suddenly, a light shined thourth the windonw, and the door bell rang again.
This is not a dream, but a real horrible fact.
作者在文章的开篇两段详细描写了外星人的形象，我觉得颇为精彩：A tremendous object totally blocked the door. It had a human like skeleton, with a round head, strong arms and legs, a waist as thick as a cow. On its face, two lighting blue dots standed(应为stood) for the eyes, and an outstanding steel line turned down into a curve--though it’s hard to read its countenance, it’s easy to feel its melancholy by its air. Besides, his fat face is covered with grey dusts, as if he came from the dustbin on earth, not the sky.
另一处则是作者对城市污染的描写：In the local industrial site, the black smoke were flying into the night sky, drifting like a lone( 应为 long)black snake, veiling all the shining stars with a stifling cloth. Enormous working trucks howling （应为howled）in the night, breaking all the peace away.这一段的描写同样充满了画面感，黑蟒一般的工厂烟雾，向一块布一般遮蔽了浩渺星辰，工厂中的卡车，在夜晚低吼。这里作者站在女孩和外星人的角度，以俯拍的视角描写污染，给读者提供了一种不一样的理解方式和维度。
本文的不足就是没有更详细地交代地球上的污染是如何危害外星人的星球的。如果没有解释，有一些读者可能会产生疑问。同时，作者对人物在不同情境下的表现可以把握得更好，比如，女孩看到地球的污染之严重，开始回忆被污染之前这些地方的模样，之后却稍显突兀地“仰天长啸”，这其中缺少了对女孩心理变化的描摹；而没有这样一个“牵线搭桥”的环节，读者可能难以更好地理解之后女孩的“desperate lou shout”是多么的desperate。