Green economy offers a new model ______ people could both protect the climate and develop the economy, according to what Li said at the International Cooperative Conference on Green Economy and Climate Change

There is a feeling in me _______ we’ll surely find a cure for Aids

We need to get to the root of the problem ________ we can solve it.

He is ____our teacher; he is also our best friend

Don’t _________ the bus until it stops.