This is____ a difficult problem ____ all of us can’t work it out.

Be sure _______ when you enter the cave. Otherwise, you’ll hit your head on the rocks.

Have you got any news from Jane about the English contest？— No. She said she ______ know when ______ be held, either.

In the exam , the you are, themistakes you’ll make.

Turn on the blender _____ about two minutes.[ ]