You've already made some serious blunders, don't make any more.

But for me the years in Nigeria were marred by serious blunders.

However, his directorship was cut short by a serious blunder.

The reporter, in turn, had made two serious blunders.

"They have made some serious diplomatic blunders," the diplomat said.

That was the first really serious blunder this detective had ever made.

But then came one of the most serious blunders in the state's political history.

I was convinced that I had made no serious blunders.

Now, John probably committed a serious blunder by splitting up his command.

Reagan began to respond with mistakes, and one of them was a particularly serious blunder.