Not until Kentuckys Mammoth Cave had been completely explored in 1972.
(A) make (B) and to make (C) thereby making (D) which it makesġ2. With age, the mineral content of human bones decreases, _ them more fragile. (A) to provide (B) be provided (C) providing (D) providedġ1. Alaska found the first years of its statehood costly because it had to take over the expense of services _ previously by the federal government. (A) as on (B) because (C) the way that (D) similarlyġ0. In bas-relief sculpture, a design projects very slightly from its background, _ some coins.
National park in Texas were created by volcanic eruptions that occurred _.Īrea (C) did dinosaurs roam the area (D) dinosaurs roaming the areaĩ. (A) An artist who, prolific (B) Is a prolific artist (C) Prolific an artist (D) A prolific artist _ the Canadian composer Barbara Pentland wrote four symphonies, three concertos, and an opera, among other works. (A) whose (B) which are (C) are when (D) whichħ. Mango trees, _ densely covered with glossy leaves and bear small fragrant flowers, grow rapidly and can attain heights of up to 90 feet. (A) Most famous scientists achieve (B) That most famous scientistsĪchieved (D) For most famous scientists toĦ. (A) it is of use (B) it uses (C) it a useful (D) it useful
The sapphires transparency to ultraviolet and infrared radiation makes _ in optical instruments. (A) do they need (B) they need (C) they are needed (D) as they may needĤ. According to some educators, the goal of teaching is to help students learn what _ to know to live a well-adjusted and successful life. (A) small enough (B) smaller than (C) so small (D) as small asģ. Computers that once took up entire rooms are now _ to put on desktops and into wristwatches. (A) the source (B) as source (C) the source which (D) because the sourceĢ. Most of the timber used by forest-product firms in the Black Hills of South Dakota.