"has changed" or "had changed" or "was changed"?

Question

If I want to say

Let's check if the entry ____, and do this and that if so.

which one should I use?

• has changed
• had changed
• was changed
• has been changed

And an explanation would be great!

Answer 1

Each of them has a slightly different meaning

note: my examples are offered as if the speaker sees that the entry is different in its various tenses

• Let's see if this entry has changed...

This is the present perfect tense, and refers only to the status of the entry being different than that which it was before.

i.e. It used to be "26" and now it is "24".

• Let's see if this entry had changed...

This is the past perfect tense, and refers to the status of the entry being different when measured at some prior unspecified point.

i.e. Last time I looked, it was "24" even though before that it was "26"

• Let's see if this entry was changed...

There are two possibilities with this wording:

In one case, "was" is the verb and "changed" is a past participle. This essentially draws attention to the entry's status with the adjective "changed". It could be written: "Let's see if this was a changed entry..."

i.e. It was "26" before; it is no longer "26" since it was "24" when I checked

In the other case, this is in passive voice. This means that there is an implicit agent that caused the entry to change. In other words, someone or something did the changing.

i.e. It was "26" before; but something changed it and it is [or it was] "24" now [or then]

• Let's see if this entry has been changed...

This is the same as "was changed" except for the verb "to be" is not past tense (was), but present perfect (has been). This means we are applying the same attention to the descriptor of the entry or using passive voice, but doing so in a manner more connected to the present. This could be written as "Let's see if this has been a changed entry..."

i.e. It was "26" before; it is no longer "26" since it is "24" (and has been for an unspecified amount of time)

-or-

i.e. It was "26" before, but something changed it and it is "24" now (and has been for an unspecified amount of time)