高考问答比a3小比a4大的纸:时态问题
来源：百度文库 编辑：高考问答 时间：2024/04/28 17:27:59
At present many scientists __________(make)a study of living things in the ocean.
为什么用are making而不用have made或were making ？？？？？
为什么用are making而不用have made或were making ？？？？？
At present现在
At present many scientists are making a study of living things in the ocean.
现在科学家们正在研究海洋生物.
At present “目前，现在”
所以句子必须用现在进行时