All the risks should be calculated in advance.This is necessary.可改写为：It is necessary that all the risks should be calculated in advance.
举一反三
- that all the risks should be calculated in advance. A: This is necessary B: Which is necessary C: That is necessary D: It is necessary
- 中国大学MOOC: Which one of the following goods should be insured against All Risks? ( )
- I think it necessary we should study hard in all our life.
- The freight forwarder would prepare all necessary documents for exporter if necessary．
- Some people believe that team projects are ____(necessary) and unfair at college. They think all assessments should be individual.