如果你想让小孩子用英语写东西，你可以这样说:
"Children, please write (something) in Engpsh."
例如:
"Children, please write a paragraph about your favorite hobby in Engpsh."
你也可以使用其他的语言提示，如 "using Engpsh" 或 "in the Engpsh language"，来让小孩子明白他们应该用英语写东西。
例如:
"Children, please write a short story using Engpsh."
"Children, please write a letter to your pen pal in the Engpsh language."
希望这能帮到你!