John has a bigger house than

[manhhiep2509]

I just encountered the question 65 in OG 13 which has a comparison problem. I hope the forum experts help me figure out it.
I made up the examples below to illustrate my question

1. John has a bigger house than that Ann previously thought

2. John has a bigger house than Ann previously thought

3. Yesterday, I took an earlier bath than those I took most days

4. Yesterday, I take an earlier bath than I took most days
--------
- which is sentence 1 or 2 correct?
I think sentence 1 wrong because "that" cannot refer to house. Am I wrong?

In my opinion, the sizes of john's house are compared, i.e. its actual size and the size Ann thought, not john's house and another house. Moreover, "that" refer to another house, so "that" need to be defined. However, i think "Ann previously thought" cannot define the second house, because A thought about the house's size not the house it self.
Please confirm the my explanation!

which is sentence 3 or 4 correct?
I think sentence 4 correct because we are comparing two different things.

Thank you.

[RonPurewal]

Your explanation of #1/#2 seems accurate.

#3 doesn't work for two reasons:
* You can't use the plural "those" to stand for the singular "bath". (You'd need "baths", which isn't there.)
* The past tense "took" doesn't make sense with a statement about what you normally do (i.e., on a regular basis). If the sentence said "... most days when I was a child" or something like that, then sure. But "most days", by itself, refers to a habitual action in the present, so you'd need "take".

In #4, both tenses are wrong.
* You can't use the present tense for something that happened yesterday!
* "Took" doesn't make sense, for the same reason explained above in #3.

[manhhiep2509]

Your explanation of #1/#2 seems accurate.

#3 doesn't work for two reasons:
* You can't use the plural "those" to stand for the singular "bath". (You'd need "baths", which isn't there.)
* The past tense "took" doesn't make sense with a statement about what you normally do (i.e., on a regular basis). If the sentence said "... most days when I was a child" or something like that, then sure. But "most days", by itself, refers to a habitual action in the present, so you'd need "take".

In #4, both tenses are wrong.
* You can't use the present tense for something that happened yesterday!
* "Took" doesn't make sense, for the same reason explained above in #3.

Thank you Ron.

I admit that I did not pay much attention about tense when I created the example.
I refined the example. Please explain about the comparison issue in the two below examples. I am not sure whether sentence 3 and 4 have the same meaning. What are compared in the two sentences, i.e. time frames or baths?

3. Today, I took an earlier bath than that I took yesterday.

4. Today, I took an earlier bath than I took yesterday.

[jlucero]

Thank you Ron.

I admit that I did not pay much attention about tense when I created the example.
I refined the example. Please explain about the comparison issue in the two below examples. I am not sure whether sentence 3 and 4 have the same meaning. What are compared in the two sentences, i.e. time frames or baths?

3. Today, I took an earlier bath than that I took yesterday.

4. Today, I took an earlier bath than I took yesterday.

These are still both wrong, because you need to add something before "than" to tell use what we are comparing. In this case, you are not comparing "I took an earlier bath" vs "I took yesterday". You are comparing WHEN you took two different baths, so you need to say "earlier than":

Today, I took a bath EARLIER THAN the one I took yesterday
or
Today, I took a bath EARLIER THAN when I took a bath yesterday

These two sentences are similar enough in meaning that the GMAT wouldn't ask you to prefer one over the other.