综合写作：
Blue-green algae (a type of bacteria)are common to bodies of water, such as lakes and rivers. High temperatures and abundant nutrients often cause massive increases in blue- green algae populations, known as algal blooms. Algal blooms deplete oxygen in the water and produce toxins that kill fish and other aquatic animals. Several methods have been proposed to help control harmful algal blooms.
Barley straw
One method is to place straw from barley (a cereal grain)in bodies of water affected by harmful algal blooms. The straw is put into nets and placed into the water. Sunlight and oxygen present in the water cause the straw to decompose. The decaying barley straw produces a chemical that
prevents new blue-green algae from growing. This control method is cheap and has been successfully implemented in many bodies of water across the United Kingdom.
Aerators
A second method involves using devices that mix air with water. These devices, known as aerators, are placed near the bottom of the body of water. Air is pumped through these underwater aerators. The air then rises to the surface and agitates the water with escaping air bubbles, causing waves to spread out over the surface. Blue-green algae require calm, still waters at the surface to form blooms; several aerators installed in a body of water can eliminate the conditions that encourage algae reproduction and thus prevent algal blooms from forming.
Ultrasound devices
A third way of controlling harmful algal blooms is by installing ultrasound devices in the water. These devices transmit ultrasound waves that have a frequency above the upper limit of human hearing. While the ultrasound waves do not harm other aquatic animals, they damage structures inside blue-green algae cells that help them float. As a result, the algae sink to the bottom of the body of water, where the algae quickly stop reproducing because there is too little light.
学术写作：
Your professor is teaching a class on business management. Write a post responding to the professor’s question.
In your response, you should do the following.
- Express and support your opinion.
- Make a contribution to the discussion in your own words.
An effective response will contain at least 100 words.
Dr. Achebe
Today, we are going to discuss how successful software and tech products are launched and marketed. When companies launch and market these products, early adopters are important. Early adopters are customers who tend to buy the latest products and like to be the first to try out new features and processes. In today’s discussion, I would like you to describe at least one advantage or disadvantage of being an early adopter. Please explain why you think this way.
Andrew
One obvious disadvantage is that early adopters probably pay a lot more for brand – new technology. When products first come out, they’re often quite expensive, but once they’ve been on the market for a while, the price usually drops. That’s why I usually wait to buy new technology.
Claire
New tech products might not always be more expensive – sometimes the company will give people a new product at a discount in exchange for trying it out and giving feedback on it. In fact, to me, that’s the biggest advantage of being an early adopter – your feedback can guide future improvements to a product. That’s a powerful feeling.
