For instance, many satellites in space are equipped with large panels whose solar cells transform sunlight directly 13 electric power.
答案：(A) into
【句型】transform A into B 固定搭配，表示「把 A 轉變成 B」，符合太陽能板將陽光轉換成電力的語意。from／with／off 都不是 transform 表達「轉變成」的正確搭配介系詞。
transform 的中文是「轉變」，你很可能想成「從陽光轉變過來」而選 from，方向剛好搞反。
先確認空格前後各是什麼：前面是 transform sunlight（把陽光轉變），後面是 electric power（電力）。轉變一定有起點與終點，這一句的起點 sunlight 已經寫在動詞後面，electric power 是終點；transform A into B 的 into 標的正是終點——變成什麼。填進去讀成 transform sunlight directly into electric power（把陽光直接轉換成電力）。同一組的說法可以一起記：change A into B、turn A into B、translate A into B，介系詞一律用 into。
from 標的是起點，但起點已經寫出來了，再用 from 會變成兩個起點；with 標的是工具或伴隨的東西，電力不是拿來轉換的工具；off 講的是離開表面或關掉，接不上 transform。
transform A into B（把 A 轉變成 B）、turn A into B（把 A 變成 B）、be equipped with（配備有）、absorb heat（吸收熱能）、solar cells（太陽能電池）、electric power（電力）。
The sun is an extraordinarily powerful source of energy. In fact, the Earth 11 20,000 times more energy from the sun than we currently use. If we used more of this source of heat and light, it 12 all the power needed throughout the world.
We can harness energy from the sun, or solar energy, in many ways. For instance, many satellites in space are equipped with large panels whose solar cells transform sunlight directly 13 electric power. These panels are covered with glass and are painted black inside to absorb as much heat as possible.
Solar energy has a lot to offer. To begin with, it is a clean fuel. In contrast, fossil fuels, such as oil or coal, release 14 substances into the air when they are burned. 15, fossil fuels will run out, but solar energy will continue to reach the Earth long after the last coal has been mined and the last oil well has run dry.