be connected to  把...连上。

Please connect the computer to the Internet.

The keyboard was connected to the computer.

be connected with  把...与...连接起来。

It serves as a bridge which connects the mainland with the rest of the world.

它是连接祖国大陆与世界其它地方的桥梁。

The mainland is connected with the rest of the world.

That solitary old man was suspected to be connected with the crime.

那个孤独的老头被怀疑与犯罪事件有关。

He was connected with the crime.他与那起犯罪与关.

be connected by  被...连接在一起。

The whole world is connected by computers and it is becoming smaller and smaller.

整个世界被电脑连在了一起，世界变得越来越小了.