Fill in the blanks using the following expressions.
1. covered
2. accumulated
3. entry
4. darkening
5. core

1. _____ to the museum is free.
2. We got to the _____ of the problem.
3. She _____ [=amassed] a fortune.
4. The lock was _____ with rust.
5. The sky was _____ rapidly.

Answer key
1. entry
2. core
3. accumulated
4. covered
5. darkening