N1 Vocabulary · Test 37

「まっとうする」 means to carry something through to completion, to fully accomplish/fulfill (a duty or mission). Among the choices, 「完了する」 (to complete/finish) is the closest paraphrase, capturing the sense of bringing a task to full completion.

• 1「継続する」 means to continue — focuses on ongoing action, not completion.
• 3「実行する」 means to execute/carry out — focuses on doing, not necessarily completing.
• 4「担当する」 means to be in charge of — describes responsibility, not fulfillment.

• まっとうする — to fulfill, carry through to completion (a duty/mission)
• 完了かんりょうする — to complete, finish

交える (まじえる) means 'to mix in, to interpose, to include (something among other things).' Option 2, '冗談を交えた和やかな雰囲気' (a relaxed atmosphere with jokes mixed in), is the correct usage. 交える is commonly used when something (jokes, criticism, humor) is inserted or blended into speech, writing, or an event.

• 1'アルバイトだった時期も交えると' should be 含める (ふくめる, to include/count in). When counting periods of time together, you 含める them, not 交える them. 交える is for mixing/interposing elements, not for totaling time spans.
• 3'心を交えてセーターを編む' should be 込める (こめる, to put into/infuse with). Putting one's heart/feelings into something is 心を込める, not 心を交える.
• 4'メッセージを交えて花束を贈った' should be 添える (そえる, to attach/accompany). Adding a message alongside flowers is メッセージを添える. 交える means to mix/interweave, not to attach alongside.

• 交まじえる — to mix in, to interpose, to include/interweave (e.g., jokes, criticism, humor into speech or an event)