用所给动词的适当形式填空。
1. This road (break) down by the flood all the time.
2. We _ (teach) how to do experiment in the lab yesterday,
3. A supermarket (build) near our building next year.
4. These flowers____ (should water). look! The soil under them is almost dry.
5. These used books____ (can reuse) by those new students.
6. Those dangerous houses _ (may damage) once again by the aftershock(余震)．
