The skill and precision of the ancient people of the

I think because it would be a wrong idiom, you always have a skill in doing something... that is what i feel, please correct me if I am wrong..

we can say ...X has Y skills to do something ??

The skill and precision of the ancient people of the American Southwest, in measuring the movements of the Sun and Moon is evidenced not only at Chaco Canyon, but also at a number of other sites.
A. in measuring the movements of the Sun and Moon is evidenced not only at
B. in measuring the movements of the Sun and Moon are evidenced not only at
C. in measuring the movements of the Sun and Moon is evidenced at not only
D. to measure the movements of the Sun and Moon is evidenced at not only
E. to measure the movements of the Sun and Moon are evidenced not only at

IMO B.. like, my mother and my father are good people
+ not only at (discussing above) ..so yea, between B and E (can't explain.. I choose IN istead of TO)

Please note that the underlined portion is a modifier clause. If we re-arrange the sentence by placing this clause in the beginning, it will make clear why "in measuring" is correct and not "to measure".

The skill and precision of the ancient people of the American Southwest, in measuring the movements of the Sun
and Moon is evidenced not only at Chaco Canyon, but also at a number of other sites.
A. in measuring the movements of the Sun and Moon is evidenced not only at
B. in measuring the movements of the Sun and Moon are evidenced not only at
C. in measuring the movements of the Sun and Moon is evidenced at not only
D. to measure the movements of the Sun and Moon is evidenced at not only
E. to measure the movements of the Sun and Moon are evidenced not only at



comma is not underlined. So "to" after comma is not right.

Can anyone explain why "The skill and precision" are considered plural

Subject-Verb agreement:
Two nouns joined by "and" make the verb plural
Jack and Jill are good students.

The skill and precision of the ancient people of the American Southwest, in measuring the movements of the Sun
and Moon is evidenced not only at Chaco Canyon, but also at a number of other sites.
A. in measuring the movements of the Sun and Moon is evidenced not only at
B. in measuring the movements of the Sun and Moon are evidenced not only at
C. in measuring the movements of the Sun and Moon is evidenced at not only
D. to measure the movements of the Sun and Moon is evidenced at not only
E. to measure the movements of the Sun and Moon are evidenced not only at

"in measuring the movements of the Sun and Moon" is a modifying clause and modifies the nouns "skill" and "precision"

I do agree that there is a problem with Comma here.