It's supposed to be really fast,这很惊险刺激

be supposed to应该；认为必须；被期望

The show is supposed to be good.

这场表演应当是相当好的。

Is this squiggle supposed to be a signature?

这歪歪扭扭的玩意儿就算是签名吗?

but he's not scared of anything.但他胆子很大

scare of (doing) sth害怕做某事

I was scared of slipping on the ice.

我害怕在冰上滑倒。

She is scared of going out alone.

她不敢一个人外出。

"failure to heed these warnings Can lead to serious injury or death...""要是不注意警告轻者致伤,重者死亡..."

lead to导致，引起

Mass unemployment may lead to social upheaval.

大批失业会导致社会动乱。

Smoking can lead to lung cancer.

抽烟可能导致肺癌。