Based on 4e, ex.1

Match the topic sentences to their supporting sentences.

It must be said, however, that there are many positive aspects to cycling to work.	First of all, it is a cheap and easy way to stay fit and healthy.
There are many advantages to animal conservation programmes.	Firstly, they help save endangered species.
However, genetically modified crops have their disadvantages.	The main one is that they may have negative effects on people's health.