A suitable thermometer should be used in a boiling liquid where a strong exothermic reaction is likely so that there will be warning and time to apply cooling.
(A suitable thermometer; should be used; L:in a boiling liquid) (a strong exothermic reaction; is; likely; so that there will be warning and time; L:a boiling liquid)
A suitable thermometer a strong exothermic reaction
should be used is
L:in a boiling liquid
likely so that there will be warning and time L:a boiling liquid