你可以这样说："Grandma is going to cook."

"Grandma" 是指奶奶，"going to" 是指将要，"cook" 是指做饭。

这句话的结构是：subject + verb + adverbial phrase + verb + object。在这句话中，"Grandma" 是主语，"is going" 是谓语，"to" 是介词，"cook" 是不及物动词。

例句：

My grandma is going to cook dinner tonight. (我奶奶今晚要做晚饭。)
Grandma said she's going to cook a special meal for us. (奶奶说她要为我们做一顿特别的饭。)
I can't wait to taste Grandma's cooking. She's going to make her famous roast chicken. (我迫不及待想尝尝奶奶的烹饪。她要做她著名的烤鸡。)