下列各句中，没有语病的一句是

I ______ sooner but I didn’ t know that they were waiting for me.

The weather that day may not be as good as expected, in ________ case we will have to put off the event.

I have no idea ______ measures the governmentwill take to stop the river from being further polluted.

The school board has teachers to spare no effort to help the students who have fallen behind in studies.