and/or

[lindaliu9273]

Hi instructors,

I'm confused about the difference between and/or in parallel.

In OG13th, #21.

#1. do not contain A, B or C
#2. do not contain A,B and C

Is #2 incorrect? Or it's correct but has different meaning with #1?

Besides, why is "anything that has been" in D better than "anything" in E? I don't know present perfect is better. Also, why "that is" is not wordy?

Thank you so much!

[RonPurewal]

Hi instructors,

I'm confused about the difference between and/or in parallel.

In OG13th, #21.

#1. do not contain A, B or C
#2. do not contain A,B and C

These don't mean the same thing.

#1 means "can't contain any of these things". This type of construction is common.

#2 would just mean "can't contain all of them"--i.e., as long as at least one of them is absent, you're good.
(e.g., Alex can quickly make friends with anyone who isn't dumb, boring, and annoying. --> As long as someone is not ALL THREE of these things, Alex will be able to strike up a friendship.)

Common sense dictates that this particular sentence has meaning #1: If you're going to call something "natural", it should contain none of those things.

[RonPurewal]

Is #2 incorrect? Or it's correct but has different meaning with #1?

Different meaning--see above.


You're unlikely to see something like #2, because it's just ... weird. It's hard to interpret at first. I can't really put a finger on exactly why, though. (The whole concept of "not all of these things" might just be non-intuitive to the human mind"”especially in comparison to "none of these things", which is highly intuitive.)

If you encounter a sentence that actually has an intended meaning like #2, it will likely be written as something like "If x, y, or z is absent..."

[RonPurewal]

Besides, why is "anything that has been" in D better than "anything" in E? I don't know present perfect is better. Also, why "that is" is not wordy?

First, "wordiness" is not actually an error.

"Anything synthesized" only works if "synthesized" can be regarded as an adjective (like "anything artificial"). Whether GMAC allows that interpretation, only GMAC can say.

If "synthesized" is a verb form, then you need "that has been..." to express the time sequence correctly.

Analogy: Say my friend doesn't like to buy second-hand clothes.
She might say:
I don't like to buy anything that has been worn already.

The point is that she can't say "anything worn", because "worn" is not an adjective. She has to say "anything that has been worn", because the clothes were worn by someone else in a previous timeframe. Similarly, the synthesis was a previous event, so "...that has been synthesized".

(Actually, "worn" IS an adjective"”with a totally different meaning, along the lines of "damaged or eroded from being used a lot""”but it can't be used as an adjective with the meaning intended here.)

[lindaliu9273]

Thank you so much!

[RonPurewal]

No problem.