Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Outcome | Year | Championship | Surface | Partner | Opponents in the final | Score in the final |
| --- | --- | --- | --- | --- | --- | --- |
| Runner-up | 1978.0 | Wimbledon | Grass | Fleming | Hewitt McMillan | 1–6, 4–6, 2–6 |
| Winner | 1979.0 | Wimbledon | Grass | Fleming | Gottfried Ramírez | 4–6, 6–4, 6–2, 6–2 |
| Winner | 1979.0 | US Open | Hard | Fleming | Lutz Smith | 6–2, 6–4 |
| Runner-up | 1980.0 | US Open | Hard | Fleming | Lutz Smith | 6–7, 6–3, 1–6, 6–3, 3–6 |
| Winner | 1981.0 | Wimbledon (2) | Grass | Fleming | Lutz Smith | 6–4, 6–4, 6–4 |
| Winner | 1981.0 | US Open (2) | Hard | Fleming | Günthardt McNamara | walkover |
| Runner-up | 1982.0 | Wimbledon (2) | Grass | Fleming | McNamara McNamee | 3–6, 2–6 |
| Winner | 1983.0 | Wimbledon (3) | Grass | Fleming | Gullikson Tom Gullikson | 6–4, 6–3, 6–4 |
| Winner | 1983.0 | US Open (3) | Hard | Fleming | Buehning Winitsky | 6–3, 6–4, 6–2 |
| Winner | 1984.0 | Wimbledon (4) | Grass | Fleming | Cash McNamee | 6–2, 5–7, 6–2, 3–6, 6–3 |
| Winner | 1989.0 | US Open (4) | Hard | Woodforde | Flach Seguso | 6–4, 4–6, 6–3, 6–3 |
Question:
What is the surface made of if the opponent in the final is Hewitt McMillan?
Answer:
Grass