Within each group, a wide range of features to choose from.

[GeneD]

Within each group, a wide range of features to choose from. It was difficult to distinguish between them. From the exercises (#4).

I don't clearly understand the general meaning of the sentences above. Maybe it's the underlined part that causes the trouble. Despite this I'll try to rephrase that example.

Within each group, there was a wide range of features to choose from, so it was difficult to distinguish between them.

Is my example correct? And what features (causing the difficulty with distinguishing) are they talking about?

[bhaisahab]

'Within each group, a wide range of features to choose from.'

As it stands the sentence doesn't make sense.

[Rover_KE]

Read the instructions again, GeneD. Your rewrite of the whole thing is correct, but that was not what you are meant to do.

You have to decide whether each component is a complete sentence or a sentence fragment.

The first part of #4 is a sentence fragment. You have to explain to a student why it is not a complete sentence.

Now, can you explain why Within each group, a wide range of features to choose from is not a complete sentence?

[GeneD]

Now, can you explain why Within each group, a wide range of features to choose from is not a complete sentence?

It hasn't got a predicate. 'A wide range of features' (or even the whole underlined part) is a subject which needs some verb to make the sentence complete. To do it, I used the 'there is' structure. (Though I'm not sure which part of that sentence is a subject, and which a verb. I've seen in some places on the web, 'there' was called a 'dummy subject', and 'is' a verb. In other places, it is said that, in the 'there is an x' example sentence, the 'x' is a subject, and 'is' a verb. I'm curious what classification authoritative sources approve.)

[Tarheel]

It doesn't have a verb that would make it a sentence. The phrase a wide range of features to choose from is a noun phrase.