Why this construction needs to be avoided? (With child-care

This "rule" came from Verbal Flash Cards I downloaded.
Two different sources of flash cards had this rule mentioned. However, none of them had examples. That is why I was confused by the "rule" and hoped somebody could clarify.

Hey fijisurf,

This is a great example of why I'm not that big a believer in flash cards for studying for the GMAT, which is more a test of how you think than of what you know. Memorizing rules, formulas, and tricks outside the context of actual GMAT questions is a pretty low return on investment to me. If you're going to use flashcards, I'd highly recommend that you make them yourself, and that you make them for things that you know that you need to emphasize.

For sentence correction, specifically, I think you're much better off looking for particular decision points and working from them. The GMAT routinely tests:

Pronouns
Subject-Verb Agreement
Verb Tense (logical timeline)
Parallelism
Modifiers

Training yourself to get really good at the above will answer just about every SC problem that you may find, and for the few problems on which you can't apply the above you'll have worked through enough problems to have more of a feel for it. Memorizing grammatical terminology is a long, cumbersome road that really doesn't need to be taken.

I agree.

Here some clarification:
https://www.manhattangmat.com/forums/pre ... t3407.html

I couldn't agree with you more. I have walked down the road of trying to learn totally new tricks. I wasted about a week learning and practicing a concept called 'speed mathematics'. It is an interesting and smart concept but actually applying those concepts during tests is very difficult.

i guess people would do it after the techniques become ingrained