Jesus uses a question to make the disciples think deeply about what he will tell them. Alternate translation: "Let me tell you something about all these buildings." (See: [[rc://en/ta/man/translate/figs-rquestion]])
It is implied that enemy soldiers will tear down the stones. This can be stated in active form. Alternate translation: "when the enemy soldiers come, they will tear down every stone in these buildings" (See: [[rc://en/ta/man/translate/figs-explicit]] and [[rc://en/ta/man/translate/figs-activepassive]])