将二氧化碳气体通入水中，在此溶液中存在的分子种类有（　　）

A．2种

B．3种

C．4种

D．5种

词形变换。

1. Don't make any _________(noise) any more. It's much too __________(noise) here.

2.____________(much) you eat, the __________(health) you'll be, because _________(eat) too much will make you ___________(health).

3. It's not ________(wise) to spend hours_______(play) football after school or _______(stay) out late.

4.She is not very ___________(sport), she can't run fast and hates swimming.

5.The problem of stress gets ___________(bad) when people don't share their problems.