（分）如图所示，在倾角为θ = 30o 的光滑斜面的底端有一个固定挡板D，小物体C靠在挡板D上，小物体B与C用轻质弹簧拴接。当弹簧处于自然长度时，B在O
_______ is reported in the newspapers, talks between the two countries are making progress. A. It B. That C. As D. What
绕有线圈的铁芯直立在水平桌面上，铁芯上套着一个铝环，线圈与电源、电键相连，如图所示．线圈上端与电源正极相连，闭合电键的瞬间，铝环向上
三种水循环在各自的运动过程中都具备的环节是 A．蒸发和降水 B．蒸发、降水和径流 C．蒸发、降水、径流和水汽输送
Michael America on a cold spring morning. A. leave B. leaves C. left
