It has not been ______ that this drug is effective against the new type pneumonia.
举一反三
- It has been found that the placebo is effective in every disease.
- 18.The new drug will not be put on the market ____ it has proved safe on humans.
- 中国大学MOOC: Ivermectin is highly effective against a range of parasites and has no side effects.
- Ivermectin is highly effective against a range of parasites and has no side effects. A: 正确 B: 错误
- Many a plan ______ to fight against pollution. A: have been worked out B: have been worked on C: has been worked out D: has been worked on