Peter, a superstar in environment protection, reduces plastic and other _______ through DIY.

It’s reported that workers on London’s underground train network will go on strike（罢工）in ________ with colleagues losing their jobs at ticket offices. 

There is no _____ that taking regular physical exercise is good for your heart.

    Eggs, meat, vegetables and other foods can easily be poisoned by microorganisms such as ______.

---How many ________ are there in your school?  ---There are fifty-five.