関連ワード:
is difficult an adjective or adverb is difficulty an adjective or adverb is hard an adjective or adverb is tough an adjective or adverb is harder an adjective or adverb is complex an adjective or adverb is the word difficult an adjective or adverb is hard material an adjective or adverb mathematics is difficult adjective or adverb is the word hard an adjective or adverb
