求助大全495,397,426

498.    Many of them chiseled from solid rock centuries ago, the mountainous regions of northern Ethiopia are dotted with hundreds of monasteries.

(A) Many of them chiseled from solid rock centuries ago, the mountainous regions of northern Ethiopia are dotted with hundreds of monasteries.

(B) Chiseled from solid rock centuries ago, the mountainous regions of northern Ethiopia are dotted with many hundreds of monasteries.

(C) Hundreds of monasteries, many of them chiseled from solid rock centuries ago, are dotting the mountainous regions of northern Ethiopia.

(D) The mountainous regions of northern Ethiopia are dotted with hundreds of monasteries, many of which are chiseled from solid rock centuries ago.（E）

(E) The mountainous regions of northern Ethiopia are dotted with hundreds of monasteries, many of them chiseled from solid rock centuries ago.

I am confused with choice D. Could someone explain this to me? In what case we use many of them or many of which?

Thank you

D. many of which ARE chiseled ... centuries AGO

  时态不对, 应该用过去时

many of which引导定语从句, 而 many of them引导同位语, 二者都对的。

类似:

379.        In good years, the patchwork of green fields that surround the San Joaquin Valley town bustles with farm workers, many of them in the area just for the season.

(A) surround the San Joaquin Valley town bustles with farm workers, many of them

(B) surrounds the San Joaquin Valley town bustles with farm workers, many of whom are

(C) surround the San Joaquin Valley town bustles with farm workers, many of who are

(D) surround the San Joaquin Valley town bustle with farm workers, many of which（A）

(E) surrounds the San Joaquin Valley town bustles with farm workers, many are

Thank you very mcuh

379.        In good years, the patchwork of green fields that surround the San Joaquin Valley town bustles with farm workers, many of them in the area just for the season.

(A) surround the San Joaquin Valley town bustles with farm workers, many of them

(B) surrounds the San Joaquin Valley town bustles with farm workers, many of whom are

(C) surround the San Joaquin Valley town bustles with farm workers, many of who are

(D) surround the San Joaquin Valley town bustle with farm workers, many of which（A）

(E) surrounds the San Joaquin Valley town bustles with farm workers, many are

What is wrong with D. should use many of whom. is it right?

For the D. It will be right if "many of which"  is changed to "many of whom are".