HSK 4
是否
shìfǒu副
whether (or not); if; is or isn't
请告诉我你是否同意。
Qǐng gào sù wǒ nǐ shì fǒu tóng yì.
Please tell me whether you agree.
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Other HSK words sharing a character
Also free:
New in the HSK 3.0 word list at level 4.