monotone
/ˈmɔnətəun; `mɑnəˌton/ n[sing]
1 (sound in a) way of speaking in which the pitch of the voice remains level and unchanging 单调（的声音）
to speak in a monotone 用单调的声音说话.
2 lack of variety, as in a style of writing （文体的）单调, 无变化. monotone, adj [attrib 作定语]
without changing the pitch of the voice or the shade of colour （声音或色彩）单调的, 无变化的
monotone concrete buildings 单调的混凝土建筑.