But experts say they are encouraged that the virus seems to be hitting hardest among people of middle age, sparing the more vulnerable groups - the elderly and children under the age of five.

VOA: standard.2009.04.28

So they're optional, but they're very, very, very highly encouraged that you do these, because this is going to give you practice for the types of problems that are going to be on the exam.

虽然它们是选做的，但是它们非常非常，非常值得你们去做，因为这对你们来说是一次训练,是用来熟悉考试题型的。

麻省理工公开课 - 化学原理课程节选

PROFESSOR: All right, I'm hearing a little of both, but I'm very encouraged to hear quite a few people saying sigma.

好，我听到了两种答案，但我很高兴听到不少人说sigma键。

麻省理工公开课 - 化学原理课程节选

Some fire chiefs in California say that residents should always be encouraged to evacuate, but Naomi Brown, from the Australasian Fire and Emergency Service Authorities Council, says installing effective early warning systems is the key.

VOA: standard.2009.06.24