As the tunnel grew longer a bowl and string were used for pulling the sand back.

As the tunnels grew longer, a number of technical innovations made the job easier and safer.

After about five minutes, the tunnel ahead grew lighter.

He frowned at the answer and calculated how long it would be before the tunnel grew too small for his team to continue on.

The tunnel grew about 18 inches each day, with both sides moving toward the center.

The tunnel grew lighter, he must be coming near the end.

It was as if the tunnel were growing a fur of cactus spikes.

The tunnel was growing in length as fast as they could run through it.

The tunnel crooked to the right and grew steadily narrower.

The tunnel crooked to the left, then to the right again, and grew narrower still.