<p>In Alaska, the ground is riddled with ice wedges, many quite ancient, caused (by the cold earth cracks) and the cracks fill with water.
A. by the cold earth cracks
B. by the cold earth cracking
C. when the cold earth cracks
D. where they crack the cold earth </p>
<h2>E. through the cold earth cracking </h2>
<h2>Because ecotours support conservation efforts and (raise awareness)of ecological (issues is why) they (have become) (increasingly popular with) environmentally sensitive travelers.</h2>
<h2>The first Asian American (to be elected) governor in the United States, George Ariyoshi of Hawaii (has served) longer (than any) of his predecessors when he retires (from) office in 1986.</h2>
<h2>In Gee's Bend, Alabama, (traditionally made) quilts (are aired) outdoors on sunny spring days, attracting local quilters who enjoy (this) display of one another's (creations).</h2>
<h2>Someone who uses a personal computer (to perform) only (such tasks as) word processing and sending e-mail (need not) buy the (most advanced) model available on the market.</h2>
<h2>Quincy took dan to Derek's home (for a visit), (never imagining) that five years (would pass) before (seeing) Derek again. </h2>
<p>Because ecotours support conservation efforts and (raise awareness)of ecological (issues is why) they (have become) (increasingly popular with) environmentally sensitive travelers.</p>
<p>“Because” makes “is why” unnecessary and awkward, So instead of (issues is why) becomes (issues,).</p>
<p>In Alaska, the ground is riddled with ice wedges, many quite ancient, caused (by the cold earth cracks) and the cracks fill with water.
A. by the cold earth cracks
B. by the cold earth cracking
C. when the cold earth cracks
D. where they crack the cold earth
E. through the cold earth cracking </p>
<p>To simplify the analysis drop the phrases “in Alaska” “many quite ancient” and the clause “and the cracks fill with water”.</p>
<p>So you have:</p>
<p>The ground is riddled with ice wedges caused (by the cold earth cracks).</p>
<p>C is the best choice in that it provides a clear reason for “why there are ice wedges”. In C “cracks” is used as a verb [subordinating conjunction _ subject + verb], whereas in (A) it’s a noun – and with (A) the sentence doesn’t then make sense, or is at best very awkward.</p>
<p>The first Asian American (to be elected) governor in the United States, George Ariyoshi of Hawaii (has served) longer (than any) of his predecessors when he retires (from) office in 1986.</p>
<p>This must be from an old test. I expect that it predates 1986 since the “correct” part of the sentence suggests that the governor will retire in 1986.</p>
<p>The problem then is with the tense “has served’”. 1986 is in the future so it should be “will have served”.</p>