“不牢靠”的英语？

这地方建造得有些不牢靠。The place is a bit jerry-built.我们的不牢靠的记者证所依仗的就是我那几篇杂志上的文章.Our flimsy journalists credentials rest on my few magzine pieces.别爬上那个梯子, 梯子不牢靠.Don t climb that ladder -- It's not secure....