The correct answer, based on the meaning of ruling "with a high hand," is oppressively, as it conveys a similar domineering and authoritarian style.
The phrase "I racked my brains to solve this difficult problem" involves the idiom "racked my brains," which means to deeply engage in thought or try hard to think of a solution. Among the given options, we must select the phrase closest in meaning to this idiom.
Let's examine the options:
Option 1: "I read a large number of books."
Analysis: This suggests gathering information or seeking knowledge, not necessarily deep thinking.
Option 2: "I consulted several people."
Analysis: This indicates seeking others' opinions or advice, but not the act of deep personal thought.
Option 3: "I used my commonsense."
Analysis: While this involves thinking, it refers to applying practical and sound judgment, not necessarily intensive thinking.
Option 4: "I subjected my mind to hard thinking."
Analysis: This directly corresponds to engaging deeply in thought, similar to the idiom "racked my brains."
The correct and closest meaning to the phrase "I racked my brains" is found in Option 4: "I subjected my mind to hard thinking."