中国大学MOOC: When the vocal folds are apart, the airstream can go through freely, and the ________ sounds are produced.

The distinction between English vowels and consonants lies in the obstruction of ( ). A: nose B: mouth C: airstream D: throat

The characteristics of Longwall Shield? A: more powerful and faster/cutting speeds exceeding 100 fpm B: shield movement can be a significant source of dust C: coal and/or rock fall from the top of the shield canopy directly into the airstream D: requires shields to advance at a faster rate

If there is no hydraulic power to extend the nose gear,the weight of the gear and the airstream pushes the nose gear into the extended position. A: 如果没有液压动力放下前起落架，起落架的重量和气流会将其推至放下位。 B: 如果液压动力未将前起落架放下, 起落架的重量和气流会将其放下。 C: 液压动力可以放下前起落架，起落架的重量和气流也可以将其推至放下位。

（英译中）If there is no hydraulic power to extend the nose gear,the weight of the gear and the airstream pushes the nose gear into the extended position. A: 如果没有液压动力放下前起落架，起落架的重量和气流会将其推至放下位。 B: 如果液压动力未将前起落架放下, 起落架的重量和气流会将其放下。 C: 液压动力可以放下前起落架，起落架的重量和气流也可以将其推至放下位。