好好(hǎo hǎo) - properly, carefully, well (reduplicated for emphasis) in Mandarin

好hǎo好hǎo学xué习xí，天tiān天tiān向xiàng上shàng。

Study hard and make progress every day.

请qǐng好hǎo好hǎo想xiǎng一yī想xiǎng。

Please think about it carefully.

你nǐ要yào好hǎo好hǎo休xiū息xi。

You need to rest properly.

你nǐ好hǎo好hǎo休xiū息xi一yí下xià。

You should have a proper rest.

请qǐng好hǎo好hǎo听tīng老lǎo师shī讲jiǎng课kè。

Please listen properly to the teacher.