Some researchers believe that there is no doubt____a cure for AIDS will be found.[ ]

The weather in London is so changeable that peoplealways take their umbrellas with them______rain[ ]

My mother often tells me _______ my classmates when they need.

There is a shortage of teachers in Western China, and it will fall on the 80s and 90s generations to this responsibility.

Haven’t I repeated that you________have a holiday on Saturday if you work hard?[ ]