The chairman thought       necessary to invite Professor Smith to speak at the meeting.

It happens in plants when gardeners take cuttings from growing plants to make new           . 

(2013·开封市高三二模) The power failure made ________ difficult for us to complete the task on time.

______side of the street is lied with different shops, _______ of which sell electronic products.

 Lily had a bad stomachache. But the doctor said there was ____________with her.