Source A: What the white sheet held

I had agreed to two hours. I had brought one coat. I had already regretted both.

The survey began at ten, in a field behind the library, where a white sheet hung between two poles and shivered whenever the wind found it. A lamp stood in front of it, throwing such a fierce square of light into the darkness that the whole arrangement looked like the saddest stage set in the county. There was no audience. There were no performers. There was only wet grass creeping through my trainers.

‘They will come,’ said Leena, opening a notebook.

I looked at the blank sheet. Nothing came.

Ten minutes passed. Then twenty. The lamp hummed, the poles creaked and the cold pushed its fingers through the seams of my coat. I began composing the message I would send when I left early: sorry, headache, early start. Anything sounded more dignified than admitting that I had been defeated by an empty piece of fabric.

‘Some nights are quiet,’ Leena said. She did not sound disappointed. She drew a neat line beneath the date and waited.

Nothing.

I had expected clouds of wings, or at least a few determined insects hurling themselves at the light. Instead, the darkness beyond the lamp seemed solid. I watched the minute hand of my phone advance with insulting confidence.

Then the sheet blinked.

A pale shape had appeared near the bottom edge. It was smaller than my thumbnail, with wings folded into a narrow roof. I almost dismissed it as a scrap of bark until it moved sideways, delicately, as if trying not to disturb the cloth.

Leena bent towards it but did not touch. ‘Look at the markings.’

Under the lamp, it was not brown at all. Fine silver lines crossed its wings. Along one edge ran a row of black dots, each one clean and separate. The insect’s head was covered in hairs so bright that they looked newly painted.

Another moth arrived, then three together. One dropped onto the sheet with the weightless bounce of ash. Another rested with its wings spread flat, displaying two circles like watchful eyes. I stopped checking the time. I began checking the darkness.

Where had they been hiding? How could so much pattern belong to creatures I had previously grouped together as ‘dust with wings’? Leena called out measurements and I wrote them down, first slowly, then fast enough to keep pace. The page filled with times, colours and small distinctions: hooked wing; red fringe; green stripe; one antenna shorter than the other.

The cold remained. Water still soaked my socks. Yet the field no longer seemed empty. Every movement at the border of the light suggested an arrival. When the lamp flickered, I held my breath until it steadied.

At midnight, Leena reached for the switch.

‘Already?’ I said.

The sheet dimmed and became ordinary cloth again. Around us, the field closed like a curtain. I looked down at the crowded notebook and wondered how the darkness could hold so much without showing any of it.

I had agreed to only two hours.

In this passage, how does the writer use language and structure to convey the narrator’s change from dismissive impatience to absorbed curiosity?

Support your answer with detailed examples from the text, including brief quotations.