Fill in the blanks using the following expressions.
1. invalid
2. fluids
3. by the dozens
4. rank upon rank
5. in session

1. ______ of caravans filled the field.
2. The treaty was declared _____ because it had not been ratified.
3. The doctor told him to drink plenty of _____.
4. The court is now _____.
5. Staff members were leaving _____ (= in large numbers).

Answer key
1. Rank upon rank
2. invalid
3. fluids
4. in session
5. by the dozens