I appreciate _____ the opportunity to work in your company two years ago.
He didn’t make ______ clear when and where the meeting would be held.
She's aiming ________ a scholarship. That is why she has been focusing her mind ________ her work.
Once you ______ the habit of smoking, it is hard to quit.
It's high time that you ________ even harder at your lessons as the exam is around the corner.
The center, dealing with children_______ to computer games, has achieved great success.