受精的标志是（　　）

已知平面向量 $\overrightarrow{a}$ ， $\overrightarrow{b}$ ， $\overrightarrow{c}$ ， $\overrightarrow{a}$ =（﹣1，1）， $\overrightarrow{b}$ =（2，3）， $\overrightarrow{c}$ =（﹣2，k），若（ $\overrightarrow{a}$ + $\overrightarrow{b}$ ）∥ $\overrightarrow{c}$ ，则实数k=（   ）

阅读理解

Worlds of Fun

    Location: Worlds of Fun is located off Highway 435 in Kansas City, Missouri.

    History: Worlds of Fun was opened on May 26, 1973, at a cost of 25 million dollars. Loosely themed around the Jules Verne book, Around the World in Eighty Days, the park was founded by Hunt Midwest Company. In 1982, Hunt Midwest bought a nearby waterpark, Oceans of Fun. In 2013, Worlds of Fun and Oceans of Fun were combined to a one ticket admission, providing all guests with access to 235 acres of amusement and water rides.

    Hours: Worlds of Fun is open from April through Halloween.

    Tickets: Buy and print online. Always try to buy your tickets in advance, to save time when you get to the park.

    Reservations: Worlds of Fun sells “Fast Lane” cards that save riders' time by allowing them to bypass the majority of wait for most of rides and attractions including Mamba, Prowler, and Patriot. Ride as many times as you want all day long.

    Strategy: Most visitors tend to begin the day with Prowler, the hottest attraction in the park. Use that tendency to your advantage and head to the Patriot first. After that, try the Dragons. Then work your way back to the Prowler. After riding the Prowler, there is only one coaster left, Mamba. Hit it next. If the park is not very crowded, you can ride Boomerang on the way to Mamba. After riding Mamba, head back for a ride on the Wolf. By then you will have tried most of the popular rides and attractions in the shortest possible time.

    News: In 2017, Worlds of Fun is adding Steel Hawk, a ride that will take guests up 301 feet in the air and spin them at a 45-degree angle for a 60-second flight. Wait to have a try!