pls, help:

Regarding Question 19-OG 11th, and some other questions

For “noun(attempt)” “doing something (trying) and “doing of something”

“Noun” is prefered to “doing something”, and “doing something” is prefered to “doing of something”; all cases is correct grammartically. Is that right?


Pls, help me. In Vietnam, there is no teachers no class for gmat.

Thang, Hanoi, Vietnam




1. regarding “in that “and “because”

From Question 208-OG10, and Question 51-OG11, I can conclude that when two choices(even one of them is A anwer which has priority of meaning) have no mistake, choose “because”, “since” or “for”. Is that right?

2. regarding Question 73-OG 11

I do not know why” like that of earlier generations” is wrong. I think “like that” here means “the goal of the young like “the goal of earlier geration”. And the use is right. Please, help me explain.


3. this following sentence come from “15test set” from retired tests, of previous years, on the internet.

Scientist have dated sharp-edged flakes of stone found in the fine-grained sediments of a dry riverbed in the Afar region of Ethiopia to between 2.52 and 2.60 milion years ago, pushing back by more than 150,000 years the earliest date /when it is known that humans make/ stone tools

a. when is is known that humans make
b. at which it is known that human had made
c. at which humans are known to have made
d. that humans are known to be makin
e. of humans who were known to make.

I do not know decide between a, and c, though c is correct, why a is wrong. Pls, explain.

Wating for your reply.
Best regards

Thang,Hanoi, Vietnam