Geologists remained doubtful about the volcano's dormancy, noting that minor tremors often precede a major eruption.
地质学家对火山的休眠状态仍持怀疑态度，指出轻微震颤往往是重大喷发的前兆。
Which choice best defines “doubtful”?
D — Feeling uncertain about something. “doubtful” means feeling uncertain about something.
Which word means “feeling uncertain about something”?
C — doubtful. “doubtful” means feeling uncertain about something.
doubtful — feeling uncertain about something. In Chinese: 不确定的，怀疑的.
doubtful is pronounced /ˈdaʊtfəl/.
Geologists remained doubtful about the volcano's dormancy, noting that minor tremors often precede a major eruption. (地质学家对火山的休眠状态仍持怀疑态度，指出轻微震颤往往是重大喷发的前兆。)
uncertain, hesitant, skeptical — all close in meaning to doubtful (feeling uncertain about something).
certain, confident — each the opposite of doubtful (feeling uncertain about something).
Yes. doubtful is on the SAT Prep Basic list — the everyday academic words the SAT assumes you already have. 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.