shí xiào
effectiveness for a given period of time
prescription (law)
aging (metallurgy)
shī xiào
to fail
to lose effectiveness
shì xiāo
marketable
saleable
appropriate to the market
shì xiāo
trial sale
test marketing
shī xiào
to laugh in spite of oneself
to be unable to help laughing
to break into laughter
shí xiào
actual effect
practical result
efficacy