After more than four decades of research and development, a new type o

I totally agree, and I find that structure to be awkward and illogical. The following alternative structures are better.

After more than four decades of research and development, being tested is a new type of jet engine that could eventually propel aircraft anywhere in the world within two hours or help boost cargoes into space at significantly lower costs than current methods permit.

After more than four decades of research and development, a new type of jet engine that could eventually propel aircraft anywhere in the world within two hours or help boost cargoes into space at significantly lower costs than current methods permit is being tested.

Regardless of whether one could debate that the structure is OK, GMAC should not have used such an illogical, awkward, unfamiliar, and debatably incorrect structure in an OA. The question should have been edited or thrown out.

(i) I bought a Mercedes, and It is green in color

(ii) John likes to sing, and Alex loves to dance.

(iii) I I bought a Mercedes, and Sam love KFC

Hello, how could relative pronoun that refer to the far away noun jet engine?

Hello, how could relative pronoun that refer to the far away noun jet engine?

it is generally my practice not to comment on made-up sentences.
That said:



A sentence in a book is provided context by the other sentences in the book.
An SC on the GMAT is different.
Because there is no context, it must offer -- all on its own - a self-contained story.

I bought a Mercedes, and it is green.
This sentence would not constitute a viable SC on the GMAT.
The story feels incomplete.
Why is the writer connecting the purchase of the car to the color of the car?
A reader has no idea.
Now consider the following:
I have always loved the colors of spring.
Yesterday I bought a car, and it is green.
Whenever I look at the car, I think of spring.
Now, a reader understands why the purchase of the car is connected to the car's color: the greenness of the car reminds the writer of springtime.

E: A new type of jet engine is being tested, and it could eventually have the capability to propel aircraft anywhere in the world within two hours.
Here, the story is incomplete.
According to the first clause, the engine is new and only now being tested.
Why is this lack of testing data connected to such an amazing capability -- the ability to propel aircraft anywhere in the world in two hours?
A reader has no idea.
While E might work as part of a newspaper article in which the other sentences can provide context, it does not constitute a viable SC.

would you agree -- the rule that the 2nd clause having to logically follow from / having to connect to the 1st clause is a bit 'subjective'. Its not as cut and dry. Maybe it looks un-related to one reader but perhaps to another reader -- it looks related

For example - regarding your question in the yellow

• I dont see any indication of lack of testing data
  
• I see the connection this way -- The Jet engine is being Tested TO CONFIRM if the engine can eventually have such an amazing capability

Since the engine is of a NEW TYPE that is currently BEING TESTED, the capability of the engine seems unknown.
I cannot envision any circumstance under which the GMAT would use and to connect to the first clause to the second.

option E)
After more than four decades of research and development, a new type of jet engine is being tested, and it could eventually have the capability to propel aircraft anywhere in the world within two hours or help boost cargoes into space at significantly lower costs than current methods permit.

I thought that if we have verbs help or start and verb right after it then it should be 'ing' so for example here it would be help boosting. Given that this is correct, I assume that it's not a case that we always need to have 'ing' after this verb. Am I right?

If I'm right, could you please send me a list of verbs after which we have 'ing' verb?