A long structure may need space to move slightly as its temperature changes. Careful desi allow sm gaps bet separate sect because ma materials exp when hea and cont when coo under ordi conditions during their useful working lives. Without suitable room for movement, adjoining parts can press against one another or pull on their connections. The required allowance depends on the material and the expected temperature range. A visible gap is therefore not necessarily evidence of incomplete construction. It can be an intentional feature that helps the whole structure function reliably.

Type only the missing letters. Each box is one letter, and the number of boxes matches the letters that are missing.