figure origin riddle joy faith grateful belief congratulate agriculture decorate commercial feature
（1）John won first prize in the English speech competition so wrote him a letter of

congratulation

congratulation

.
（2）The product is not yet

commercially

commercially

available.
（3）This important

harvest

harvest

festival takes place after all the crops have been harvested.
（4）He tried to prove that he was a

faithful

faithful

servant.
（5）To my great

joy

joy

，my wife-an angel in white-came back，safe and sound.
（6）The scientists around the world are devoting themselves to studying the

origin

origin

of COVID-19.
（7）I'd like to express my

gratitude

gratitude

to my teacher for her help.
（8）In order to own a slim

figure

figure

she decides to take exercise regularly from now on.
（9）Scientists hold the

belief

belief

that cloning may lead to many important scientific breakthroughs.
（10）They are busy

decorating

decorating

the room because of the wedding on May Day.
（11）An interesting

feature

feature

of the city is that it is surrounded by mountains.
（12）See if you can solve this

riddle

riddle

.