Contact Clause

The intended sentence is きのう かった ほんは おもしろかったです  – The book I bought yesterday was interesting. So the answer is d. ほん.

This sentence is a combination of 2 sentences.

わたしは きのう ほんを かいました。I bought a book yesterday.

その ほんは おもしろかったです。 The book was interesting.

In order to combine 2 sentences by making one into a contact clause, you need to follow these steps:

1. Decide which sentence to keep as the main sentence and which to convert into the contact clause.
   In this pair, you won’t know if the book is interesting until you read it, so you need to keep the second sentence “The book was interesting” as the main sentence and the first one “I bought a book yesterday” to convert into a contact clause.
2. Convert the secondary sentence into the plain form but you need to remember:
   1. [change は to が] If the doer of the action of the verb (= the subject) in the secondary sentence is marked with the topic marker は, this は has to be changed to the subject marker が (or の) as no phrase in the contact clause can be the topic of the sentence any more.
   2. [skip the noun] You need to skip the noun which appears in both sentence together with its particle (in this example, ほんを, the book)
      ⇒ わたしが きのう ほんを かった
3. Place the contact clause in front of the same noun you have skipped above.
   ⇒ わたしが きのう かった （その）ほんは おもしろかったです。(The (very) book I bought yesterday was interesting.)
   If the noun in the main clause has この/その/あの in front of it like this example, you can usually skip この/その/あの. If you leave them in the sentence, it adds the meaning of “one and only” to the noun.
   ⇒ わたしが きのう かった ほんは おもしろかったです。(The book I bought yesterday was interesting.)
4. Tidy up.  You can remove any obvious parts which can be left out. In this case, わたしは is not needed.
   ⇒ きのう かった ほんは おもしろかったです。

Let’s have a look at how the contact clause ends depending on the words we use:

Verbs

non-past	ほんを よむ ひと	the person/people who reads/read books
past	ほんを よんだ ひと	the person/people who read the book
negative	ほんを よまない ひと	the person/people who doesn’t/don’t read books
negative past	ほんを よまなかった ひと	the person/people who didn’t read the book

いadjectives

non-past	かみが ながい ひと	the person/people who has/have long hair
past	かみが ながかった ひと	the person/people who had long hair
negative	かみが ながくない ひと	the person/people who doesn’t/don’t have long hair
negative past	かみが ながくなかった ひと	the person/people who didn’t have long hair

なadjectives

non-past	すしが すきな* ひと	the person/people who likes/like sushi
past	すしが すきだった ひと	the person/people who liked sushi
negative	すしが すきじゃない ひと	the person/people who doesn’t/don’t like sushi
negative past	すしが すきじゃなかった ひと	the person/people who didn’t like sushi

nouns

non-past	こどもが だいがくせいの* ひと	the person/people whose child is a university student
past	こどもが だいがくせいだった ひと	the person/people whose child was a university student
negative	こどもが だいがくせいじゃない ひと	the person/people whose child is not a university student
negative past	こどもが だいがくせいじゃなかった ひと	the person/people whose child was not a university student

As stated above, when you use a non-past clause which ends in a なadjective + だ, you need to change the ending だ to な. If the contact clause ends in a noun + だ, then the だ needs to be changed to の.

Also, as shown below, the subject marker が within a contact clause is often replaced with の without causing any meaning change. However, some が cannot be replaced with の, so don’t change it unless you are sure.

People who have little rubbish are usually rich.
ゴミがすくない人ひとは、たいていお金かね持もちです。
ゴミのすくない人ひとは、たいていお金かね持もちです。

If you are finding contact clauses difficult, I have compiled a series of questions as “Basic Contact Clause Module” as part of my “Basic Grammar Exercise Modules” to help you practise on this sentence pattern. Reading about the grammar points makes you understand the pattern but understanding the pattern and being able to use it are two different things. You need to practise using the pattern upon understanding it.

The exercise includes questions to rewrite sentences using a contact clause, to practise identifying a contact clause and to place words in the correct order, just like you tried in this question. These modules are offered as a subscription and you can attempt questions as many times as you like during your subscription period. Questions are pulled out of my data base each time you attempt it, so you are likely to come across different questions if you are attempting it multiple times. Your answer will be marked straight away and the correct answer and some explanation will be displayed immediately so that you don’t have to wait for the feedback. If you are interested, please read more here. Other topics available for subscription are listed below.