The explanation came a week later. It was about ten o' clock at night; I had been dining by myself at a restaurant, and having returned to my small apartment, was sitting in my parlour, reading I heard the cracked tinkling of the bell, and, going into the corridor, opened the door. Stroeve stood before me.

"Can I come in?" he asked.

In the dimness of the landing I could not see him very well, but there was something in his voice that surprised me. I knew he was of abstemious habit or I should have thought he had been drinking. I led the way into my sitting room and asked him to sit down.

"Thank God I've found you," he said.

"What's the matter?" I asked in astonishment at his vehemence.

I was able now to see him well. As a rule he was neat in his person, but now his clothes were in disorder. He looked suddenly bedraggled. I was convinced he had been drinking, and I smiled. I was on the point of chaffing him on his state.

"I didn't know where to go," he burst out. "I came here earlier, but you weren't in."

"I dined late," I said.

I changed my mind: it was not liquor that had driven him to this obvious desperation. His face, usually so rosy, was now strangely mottled. His hands trembled.

"Has anything happened?" I asked.

"My wife has left me."

上面节选中， I was convinced he had been drinking 这里和he had drunk 究竟有什么差别呢？我体会不出差别。

另外，作者在描述当时的状态时， 为什么不是过去进行时His hands were trembling 呢？ 用 His hands trembled. 过去时说明过去某一时刻动作发生了，是说当时颤抖过了，还是一直在颤抖？ 显然，应该是一直在颤抖，

那么为什么不是用过去进行时呢？