It is known that some great scientific __________ (discover) occurred by chance.
As soon as the __________ (produce) are introduced to the market, they enjoyed great success.
We like the __________ (convenient) of shopping online, but worry about its safety.
Compared to the parents' __________ (expect), what we have achieved is too little.
He has become so fat that he was beyond __________ (recognize).
Every student had an __________ (apply) form in his hand, but no one knew whom to send it to.
They are busy with their study and only see each other very __________ (occasional).
He had promised to go with us, but he changed his plan __________ (abrupt).
The people who suffer from sandstorms know the __________ (important) of environmental protection.
As time went by, the plan he made proved fairly __________ (practice).