The lava was so viscous that it advanced only a few meters an hour, building a steep dome above the vent.
熔岩黏稠到每小时只前进数米，在火山口上方堆起陡峭的穹丘。
Which choice best defines “viscous”?
D — Thick and sticky; not flowing freely.. “viscous” means Thick and sticky; not flowing freely..
Which word means “Thick and sticky; not flowing freely.”?
C — viscous. “viscous” means Thick and sticky; not flowing freely..
viscous — Thick and sticky; not flowing freely.. In Chinese: 黏稠的;半流体的.
viscous is pronounced //ˈvɪskəs//.
The lava was so viscous that it advanced only a few meters an hour, building a steep dome above the vent. (熔岩黏稠到每小时只前进数米，在火山口上方堆起陡峭的穹丘。)
thick, gluey, syrupy — all close in meaning to viscous (Thick and sticky; not flowing freely.).
runny, fluid — each the opposite of viscous (Thick and sticky; not flowing freely.).
Yes. viscous is on the SAT Prep Difficult list — the higher-register words that decide the hard questions. The Digital SAT does not test vocabulary in isolation; words like this one are tested through Words in Context questions, where you choose the word that completes a passage most logically and precisely.
visc(黏) → 稠得难流。