果蝇的长翅（V）对残翅（v）为显性，但纯合长翅品系的幼虫，在35 ℃条件下培养成的成体果蝇为残翅。下列叙述正确的是（   ）

用所给动词的适当形式填空，完成短文

 Children’s Safety

I ____(talk) to some students. I ____(ask) about safety rules when they ____(be) younger. Their rules were very good.

John ____(say), “I couldn’t play in the kitchen.” His mum and dad didn’t ____(like) that.

Jennifer ____(can) play the piano and she could also ____(play) games in the living room. When her mum and dad ____(not, be) home, she couldn’t cook.

Tom could play in the bedroom or the living room. He couldn’t ____(play) in the bathroom or the kitchen.

What ____(be) your safety rules when you were young? ____(talk) to younger students about these and ____(help) them.

等腰三角形一底角为50°，则顶角的度数是（）