Hi Ron,
I"˜m so confused. in the correct answer, "but" is followed by "without success", just a phrase. You have said "but" must be followed by a clause unless it connects two same structures. But option A does not meet the two conditions.
Thanks in advance!

Hi Ron, I"˜m so confused. in the correct answer, "but" is followed by "without success", just a phrase. You have said "but" must be followed by a clause unless it connects two same structures. But option A does not meet the two conditions. Thanks in advance! well, tech...

HI Ron,
In A, is "on account of"can only be followed by a noun but not gerund phrase? the same use as "because of".

Hi Ron,
In option d, is "and so" redundant? i think we cannot use both "and" and "so". they are both conjunction.

tim Wrote:Correct. If either construction is used, then there must be a noun as the object of the preposition.

Thanks tim!

hi tim,
in answer A, "has emerged" is inserted into "clear picture" and "of the patterns and causes", but noun 1 of noun 2 is not allowed to be separated. i'm confused. So i think b is better than a.

i choose b because i think, a reasonably clear picture of the patterns of ocean currents and their causes have emerged. so "have" is needed but not "has".

Thanks Ron!!!

Ron,
in the correct answer, which noun is "compared with 20 percent in 2000" modified?