题目选项分析

Unlike amateur clammers, who usually dig clams by hand during the summer, professional clammers working year-round use all-weather instruments like hydraulic dredges or 20-foot-long implements known as a bull rake.

Unlike amateur clammers, who usually dig clams by hand during the summer, professional clammers work year-round, using all-weather instruments such as the dredge or a 20-foot-long implement known as a bull rake.