Ladies and gentlemen, I have the great privilege____introducing our speaker for tonight.

29. The computer system _______ suddenly while he was searching for information on the Internet.

The Somali robbed frequent attacks on the sea urged the United Nations _____to all nations to takeimmediate action.

When parents come to visit our school last week, Tom _______ them into the classroom.

－I my keys in the room yesterday. I had to get in the window. －It’s dangerous to do that.