Is there an object in this sentence?

You need to practise your proofreading.

In this sentence, "you" is the subject and "need" is the verb. But is there an object? At the moment I am guessing that there isn't and that to practise your proofreading is just a phrase.

I asked someone else and they too did not think there was an object.

Solution 1:

1. You need [to practise your proofreading].

One test to see if a phrase is an Object in a clause is to see if the phrase concerned can become the Subject of a passivised version of that clause. If it can, even if the result is awkward, then it is definitely an Object. If it can't then it is much less likely to be an Object -- but it still might be.

The noun phrase your proofreading will indeed become the Subject of a passivised version of the clause that it occurs in:

• 2. You need [your proofreading to be practised]. -- (passivised)

This shows that, in version #1, your proofreading is an object of the clause headed by practised (which appears in brackets). Of course this means that your proofreading (in version #1) has the syntactic function of Object in relation to this clause. It is not however the direct object of the sentence (version #1) as a whole.

In the original example,

1. You need [to practise your proofreading].

the sentence has a Subject, You. The predicate consists of the Predicator (read that as meaning "verb"), need, and the complement of that verb, which appears in brackets and is: to practise your proofreading. This complement is an infinitival clause. Whether you regard this infinitival clause as the object of the verb need depends on which grammar you subscribe to. Notice, however, that if we try to passivise the sentence by making this complement the subject, the result is not good. Indeed we may well regard it as ungrammatical:

• 3. *[To practise your proofreading] is needed.

For this reason, as well as many others, many grammarians (such as Postal or Huddleston & Pullum) reject the idea that such infinitival clauses are the direct objects of the verbs in such constructions. The Cambridge Grammar of the English Language describe the syntactic function of such clauses as catenative complements ruling out their status as direct objects. However, this debate is an ongoing one.

The Original Poster's question

The main clause headed by the verb need here may or may not have a direct object, depending on which grammar framework you use. However, if it is a direct object, it is an atypical one. The clause embedded in this sentence, headed by the verb practise does indeed have a direct object, the noun phrase your proofreading.

Solution 2:

What a lot of wrong answers! (Except for John's, of course.) In "You need to practise your proofreading.", the subject of "need" is (as you say) "you", and the object of "need" is "to practice your proofreading". A test for objects is whether they can be passivized, and here we have "To practice your proofreading is needed". A test for noun phrases is whether they can be pronominalized, and here, we have "(...Practice your proofreading ...) You need it."

"To practice your proofreading" is a nominalization of the sentence "you practice your proofreading", which means the sentence has been converted into a noun phrase, where it can stand where noun phrases generally stand, for instance as direct object. That is what is going on in this example, where you practicing your proofreading is said to be what you need.