Read the excerpt from The Evolution of Useful Things. But since it is 3M's policy (and that of other enlightened companies) to allow its engineers to spend a certain percentage of their work time on projects of their own choosing, a practice known as "bootlegging," Fry was able to gain access to the necessary machinery and materials and to spend nearly a year and a half experimenting and refining his idea for sticky – but not-too-sticky – slips of paper that could be used for "temporarily permanent" bookmarks and notes. Which statement best describes the relationship of ideas in this text? A cause-and-effect relationship is signaled by the words "But since." A cause-and-effect relationship is signaled by the words "their own choosing." The passage of time is signaled by the words "of their work time." The passage of time is signaled by the words "a practice."

The “big dig” the “big dig” (the central artery/tunnel project) has been complex and challenging. located in boston, massachusetts, this tunnel is eight lanes wide and three-and-a-half miles long. what is most amazing about this tunnel is that it is constructed under a major highway and skyscrapers located in boston’s financial district. construction crews used “clamshell excavators” during this dig. these machines carved narrow trenches, and then a special substance was pumped into the trench to keep the dirt from caving in. finally, steel beams were lowered into the trench and concrete was pumped in. one problem that engineers faced while constructing the tunnel is the fact that the soil beneath boston is extremely loose and soggy. engineers solved this dilemma by freezing the soil and pumping very cold water into pipes beneath the city. to strengthen the soil even further, a special type of glue was injected into the ground to with the consolidation of the soil. 23 which phrase best defines the word excavator as used in the passage? a. a device used to measure underground temperatures b. a device used to level uneven surfaces c. a device used to move heavy objects d. a device used to dig holes