问题 选择题

如果鱼缸长期不换水,水缸内壁会出现一层绿膜.这层绿膜最可能是(  )

A.藻类植物

B.苔藓植物

C.草履虫

D.病毒

答案

自然界中藻类植物的数量极为庞大,分布也十分广泛.藻类植物能进行光合作用,不仅给鱼类提供了饵料和氧,而且是大气中氧的重要来源. 养鱼缸中长时间不换水,其内壁长出绿膜,水会变成绿色,就是因为藻类植物增多了.

故选:A

阅读理解与欣赏
选择题
Wondering if you’re overdue? Here are 4 signs. It’s time to rest and recharge yourself with a much-needed getaway, along with our suggestions of where to go.
Working Overtime Is Your Life

If long hours are part of your job and you’re not willing to find different work, book off some vacation days. Vacations give us something to look forward to when the daily hard work is weighing us down.
• REST up at a destination spa (度假式水疗).
• RECHARGE your batteries on a skiing vacation.
You’ve an Unhealthy Way of Life

Only time can mend a broken heart, but spending time with your best friends may speed things along. Plan a girlfriends’ getaway or guys’ weekend immediately!
• REST by the fountain at a hot see-and-be-seen LA boutique hotel.
• RECHARGE on a shopping trip or at a non-stop party hotspot.
You’re Nursing a Broken Heart

Though it’s possible to kick bad habits like smoking or over-eating at home a trip abroad may make it a bit easier. On a vacation with healthy lifestyle habits at the centre, you’re forced to focus on self-care in a way which would prove impossible at home.
It’s not enough to take care of your health on the rare occasion you can go on vacation: use vacations to kick-start a healthier lifestyle which is sustainable on a daily basis when you get back home. 
• REST a troubled mind at a yoga retreat.
• RECHARGE energy levels by the sea.
You’ve Got No Skills Left To Improve

Challenging ourselves to carry out new tasks keeps our bodies and minds active. If you’re an expert at everything and a newbie (新手) at nothing, it’s time to move outside your comfort zone. Travel is renowned for providing that opportunity for growth.
• REST your body while challenging your brain, by learning a language abroad.
• RECHARGE yourself with a healing art like massage-therapy or a cooking course.
小题1:According to the leaflet, a vacation trip will _____.
A.cure you of your heart trouble
B.help you to learn some new things
C.make you interested in your work
D.allow you to make some new friends
小题2:If you have an unhealthy lifestyle, _____.
A.a trip abroad will enable you to get rid of some bad habits easily
B.you are likely to restore your old habits once you return from a trip
C.you will learn about its harmful effects at the centre on a vacation
D.it is difficult for you to show your self-control in your own house
小题3:Where should you go if you want to get rid of your tiredness?
A.To a fountainB.To a snowy field.
C.To a hotspot. D.To some stores.