Is/am/are + to (To express instructions, responsibilities, or expected actions)

Planned or Time tabled Future Actions 

Is/am/are + to :

In English, the phrases "is to," "am to," and "are to" are typically used to express obligation, duty, or a plan of action. They indicate that someone or something is expected or required to do something. Here are a few examples to illustrate their usage:

1. "Is to":

   • "The meeting is to start at 9 a.m." (The meeting is scheduled or expected to begin at 9 a.m.)
   • "He is to complete the report by tomorrow." (It is his duty or obligation to finish the report by tomorrow.)

2. "Am to":

   • "I am to meet with the client this afternoon." (It is my responsibility or plan to have a meeting with the client in the afternoon.)
   • "She is not here because she is to attend a conference." (She is absent because she is obligated or expected to participate in a conference.)

3. "Are to":

   • "The students are to submit their assignments by Friday." (The students have a requirement or obligation to hand in their assignments by Friday.)
   • "They are not allowed to leave until they are told to do so." (They have to wait until they receive permission or instruction to leave.)

These phrases convey a sense of necessity, instruction, or expectation regarding future actions or plans.

Was/were + to :

The construction "was/were + to" is used in English to express an intended or planned action in the past. It indicates that something was scheduled, expected, or supposed to happen, but may or may not have actually occurred. Here's how it is used:

1. "Was/were + to":
   • "He was to meet me at the restaurant, but he never showed up." (He had the intention or plan to meet me at the restaurant, but he didn't actually do it.)
   • "We were to go on a trip last summer, but it got canceled." (We had planned or intended to go on a trip last summer, but circumstances prevented it from happening.)

The construction "was/were + to" is used in the past tense and can be used with both singular (was) and plural (were) subjects. It conveys a sense of expectation or intention regarding a planned action in the past.

It's important to note that this construction is more commonly used in formal or literary contexts, and in spoken English, it may be replaced by other expressions like "was/were supposed to" or "was/were going to."