閱讀 ARTISANS AND INDUSTRIALIZTION - 英檢

Paragraph 5: In this newly emerging economic order, workers sometimes
organized to protect their rights and traditional ways of life. Craft workers
such as carpenters, printers, and tailors formed unions, and in 1834
individual unions came together in the National Trades' Union. The labor
movement gathered some momentum in the decade before the Panic of 1837, but
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in the depression that followed, labor's strength collapsed. During hard
times, few workers were willing to strike* or engage in collective action.
And skilled craft workers, who spearheaded the union movement, did not feel a
particularly strong bond with semiskilled factory workers and unskilled
laborers. More than a decade of agitation did finally bring a workday
shortened to 10 hours to most industries by the 1850’s, and the courts also
recognized workers' right to strike, but these gains had little immediate
impact.

6.The phrase gathered some momentum in the passage is closest in meaning to
○Made progress
○Became active
○Caused changes
○Combined forces

請問答案為什麼是Made progress?

除了Caused changes是肯定不對 其他選擇為什麼不對?

謝謝:)

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