前些日子发表的有关植物入侵的介绍，由于本人水平有限，母语又不是英语，自然错误难免，避免误人子弟，今天请来自英国的Baker先生帮忙做了修改，以下是改完后的样子, 后面附有我对他专业问题的回答，供参考

Introduction

Good morning, ladies and gentlemen. My name is Lei Ning. Today I am glad to give a presentation about plant invasion. The purpose of this presentation is to let you to understand “what plant invasion is”. I’ll try to answer all of your questions after the presentation.

Now I’ll show all of you the framework of this presentation. First of all, a brief introduction of plant invasion will be given to you. Then I will give some examples for clarifying “how the things happened”. After that recent studies will be shown. Finally I will sum up the main points.

Main body

Firstly, I want to ask a question “how did you feel when you heard the term invasive species? (Interaction with audience part)

General speaking, the study of invasive species is a secondary discipline of plant ecology. It mainly focuses on the behavior of exotic plants after being introduced to a new ecosystem. Since the start of the new millennium, and especially with the globalization of international trade, more and more plant species have spread to the rest of the world. Because some of them are quite unfriendly, plant invasion studies are a valuable tool for understanding and providing a means for better control of this problem, although most of the research   is still only theory. Then something happened, and attention changed to the question of “how it works?” rather than solve the environmental problem posed at the beginning. Actually, plant invasion has been the norm for a relatively long time. For one thing, invasive plant species disturb the balance of the ecosystem (e.g. reduce biodiversity and compete with other native species), with obviously bad results. For another thing, plant invaders need a suitable situation, and it is conditional dependence (including spatial and temporal).

For most stable and healthy ecosystems, the relative numbers of each species remain in balance. Each of them acts like a defender and protects against invasive species from abroad. Although some natural communities look harmonious, native defender and invader are fighting each other all the time. So these scenarios seem to be battles or wars in a sense.

In order to win the battle against invasive species, new weapons need to be utilized never seen before. The basic process is evolution (some more details) for both. For chemical novel weapons, in the last 50 years, most of studies overwhelmingly focused on invaders’ preparation instead of their enemies.

Recently, we pay attention to the defenders’ side contrasting with previous studies for an objective and impartial view. Almost all of our research mainly revolves around three scientific questions:

1 What weapons do they use for a battle?

2 How do they use those weapons?

3 Why do the weapons work/not work?

(Talking something more detail….)

When we get the results, we publish that as a paper in a journal after further analysis. Although one case was born from then, we need more evidence.

Actually, there are thousands of invasive and millions of native plant species. So I only want to say: we’ve only just begun!

Conclusion

So let me summarize what I’ve just said.

Firstly, a brief definition has been discussed about plant invasion for both general and scientific interest.

Secondly, we can see how the scientific item: using novel weapons has been proposed.

And then one example of our group’s recent studies has been clarified.

I therefore recommend that it is quite important to adhere to long-term research for observing invasive plant behavior.

Many thanks for your attention. Are there any questions?

附：Baker先生的来信

Hi Lei,
Thank you for sending me the paper.
I've changed a few things, but I think the main point is clear:
Invasive plant species are a problem when they destroy native ecosystems - is this correct?
One of the results is that creatures further up the chain are affected because their food supply is destroyed (I have rhododendron in Scotland in mind, where nothing can feed off it and it poisons the soil).That said: There must be a number of species which simply fail to establish themselves because they cannot adapt to the conditions they find themselves in, making them irrelevant. No species is trying to 'do' anything; they simply follow their 'programme'. In this sense there must be creatures which are benign - for example the different types of ladybird we see, or those species which contribute to the new system they are in.

A last point: Agriculture must also be catastrophic for native species too, mustn't it? Please write to me for further clarification if my notes are not clear.
Best regards,
Jonathan

我给予的回复如下：

Hi Mr. Baker,

Thanks for revision.

Generally speaking, the first statement is correct because that is the original motivation to study invasive species. However, some researchers have different viewpoints because something new harm related was been found for recent years.

Second statement is quite interesting! Some “new guys” might find their position in a new family. It belongs to establishment procession including both passive and active reaction. But it is only stay in establishment stage, and there are dynamic future waiting for them to overcome at certain more large scale.

Yes, indeed. Due to competition by some “strong” native competitors, agriculture might also be catastrophic too. However, both at native range, they have experienced co-evolution for a long time. Somehow, as native species, they know each other relatively more than aliens. Sometimes, the harm in agriculture is more “acceptable and mild” than alien.

Best,

Lei