To my mind, the secret to happiness _____ your successful work and your contribution towards others' happiness.
| A．results in | B．consists in | C．brings in | D．takes in |
Not until World War II ______ to use new chemical techniques to purify penicillin.
| A．they managed | B．that they managed |
| C．did they manage | D．they didn’t manage |
--- What did the manager say at yesterday’s meeting?
--- So you______ to him carefully.
| A．won’t listen | B．weren’t listening |
| C．hadn’t listened | D．haven’t listened |
--- Did Jack come back early last night?
--- Yes. It was not yet eight o’clock ______ he arrived home.
| A．before | B．until | C．when | D．af ter |
In some countries citizens are ______ to vote, and if they don’t they get fined.
| A．demanded | B．suggested | C．prevented | D．required |
We’ve been looking at houses but haven’t found ______ we like yet.
| A．them | B．ones | C．it | D．one |