Thebasicunitinthestudyofmorphologyis______.
B
正如音位是音系学研究中的基本单位一样，词素是形态学研究中的基本单位。
Ifyouarewalkingawayfromaclocktower，youwillhearthetickingoftheclockfadetoapoint________itcannotbeheard.
The old couple have been married for 40 years and never once _______ with each other.
Johnson was ________ unknown before running for the presidency.
The thief took away the woman ’s wallet without ________.