Related Clues:

• Strained
• Hit hard
• Worked like a dog
• Slaved away
• Worked
• Did the job
• Worked hard
• Did the trick
• Was successful
• Moved through mud
• Walked wearily
• Put one's back into it
• Worked long and hard
• Worked hard and long
• In 21 across the alternative to potassium went well