?ahead的中文意思是“在前面，向前”，是一個副詞。它可以表示時間、空間或者行動的先后順序，也可以表示某種程度上的領先。

用法：

1. 用作時間副詞，表示提前或者在未來某個時間。：

- The meeting is scheduled for 2 p.m., but I'll arrive ahead of time. (定于下午2點，但我會提前到達。)

- We need to plan ahead for our summer vacation. (我們需要提前計劃夏季假期。)

2. 用作空間副詞，表示在某物或者某人的前面。：

- The car drove ahead of us on the highway. (汽車在高速公路上超過了我們。)

- She walked ahead of her friends to lead the way. (她走在朋友們的前面帶路。)

3. 用作行動副詞，表示向前移動或者繼續進行某項活動。：

- The team is determined to move ahead with the project despite the challenges. (盡管面臨挑戰，團隊決心繼續推進這個項目。)

- We need to stay focused and keep moving ahead towards our goals. (我們需要保持專注并朝著目標不斷前進。)

4. 用作程度副詞，表示比其他人或事物更領先或更進步。：

- Our company is always striving to stay ahead in the industry. (我們公司一直在努力保持在行業中的領先地位。)

- She is ahead of her peers in terms of academic achievements. (在學業成就方面，她比同齡人更出色。)

例句（中英對照）：

1. We need to plan ahead for our summer vacation.

我們需要提前計劃夏季假期。

2. The car drove ahead of us on the highway.

汽車在高速公路上超過了我們。

3. The team is determined to move ahead with the project despite the challenges.

盡管面臨挑戰，團隊決心繼續推進這個項目。

4. Our company is always striving to stay ahead in the industry.

我們公司一直在努力保持在行業中的領先地位。

5. She is ahead of her peers in terms of academic achievements.

在學業成就方面，她比同齡人更出色。

同義詞及用法：

1. In front of：表示位置或者順序上的前面。

- The store is just ahead, on the left side of the street. (商店就在前面，在街道的左側。)

- I'm always one step ahead of my compes in terms of innovation. (在創新方面，我總是領先于競爭對手一步。)

2. Beforehand：表示提前準備或者安排。

- Please let me know beforehand if you are not able to attend the meeting tomorrow. (如果明天你不能參加，請提前讓我知道。)

- The chef always prepares the ingredients beforehand to save time during cooking. (廚師總是提前準備食材，以節省烹飪時間。)

3. Forward：表示向前移動或者發展。

- The train is moving forward to its final destination. (火車正在向它的最終目的地前進。)

- We need to move forward with our plans, rather than staying stuck in the past. (我們需要推進計劃，而不是停留在過去。)

4. In advance：表示提前做某事。

- You need to book tickets in advance if you want to attend the concert. (如果想參加音樂會，你需要提前預訂門票。)

- I always like to plan my schedule in advance to avoid any last-minute changes. (我總是喜歡提前計劃我的日程，以避免任何臨時變化。)

5. Leading：表示領先或者占主導地位。

- He is the leading expert in this field and his opinion is highly valued. (他是這個領域的頂尖專家，他的意見受到高度重視。)

- The company has been leading the market for years with its innovative products. (多年來，這家公司一直以其創新產品引領市場。)