I put the medicine on the top of the desk to make sure it would not be _____ to my son.

Yesterday our head teacher made such an　____　speech that we all felt　_____. 

All the candidates present at the conference have contributed to the development of our country, so they are each recognized specialists in their _________fields.

There appeared an _____ look on her face on hearing the _____ story.

We made plans for a visit but _____ difficulties with the car prevented it.